Document RJqyrOGGJ94Lpmx2daKXk0GzE

DESCRIPTION: "An Epidemiological Study of Lung Cancer in Asbestos Miners," published version by Braun and Truan. Exhibit includes the following: 1) Version: Reprint from the A.M.A. Archives of Industrial Health, June, 1958, Vol. 17, pp. 634-653, Copyright 1958, by A.M.A., stamped From Industrial Hygiene Foundation; 2) Version: American Medical Association Archives of Industrial Health, Vol. 17, June 1958; 3) Version: Typewritten article that appears as it was submitted to A.M.A. including Affidavit of David S. Egilman dated May 8, 2006; 4) Affidavit of Dr. Herbert Stokinger attaching Exhibit A: Letter to Dr. Daniel C. Braun, Medical Director, Industrial Hygiene Foundation of America, Inc. dated January 20,1958 from Herbert E. Stokinger, Ph.D., Acting Editor, AMA Archives of Industrial Health SC-ALL-09830 SCF-FA-4780 1 PLAINTIFFS EXHIBIT WV-00402 PLAINTIFF'S j! EXHIBIT \{ 1Q<?3.0< RifrUt*4 /r IW A. A/. A. Artk*** #1 /--* tw, va. a. th ///*A Cfyr^r /9J4, by American HffHfct FROM An Epidemiological Study of <<!S)U^i*LAveT01 Lung Caocer in Asbestos Miners 04KIII C SSAUM. Ht. v4 t. OAVIO fSUAM, M-A_ WtaSwgb h "l^T'pa" Ever since the pronounced increase in the inddcncc oi lung cancer among males became apparent, there have been attempts to associate it with one or another of the various dements in the environment of man. The approach used by some workers has been to suspect one or several sub stances and then set about in an iremsive search for lung cancer among persons who have had any exposure to those materials. In this connection. Smith" writes: "The tenderer of authors reporting the coincirlental occurrence of primary lung cancer with silicosis or with any other theoretical etiologic conditions, has been to emphasise the percentage relationship - in extremely small series of cases, with control cases which arc not in any way comparable." It would seem inevitable that asbestos should come under scrutiny in this manner, because prolonged exposure to this material b known to cause a specific type of pneu moconiosis, and bemuse persons who show this form of pneumoconiosis often cane to ' autopsy and provide a ready source of material for study. It was in this wsy that reports of the simultaneous occurrence of lung cancer and asbeslosis began to accu mulate after the report of a case by Lynch and Smith** in 193S. Within the next 10 years, about IS additional cases were re ported. and In I9S4 M crewether * reviewed aO deaths from asbestosis recorded in Eng land since Starch. 1924. Lung cancer oc curred in 165s of these cases. Glovne.*' Accepted lot publication Jan. A I9S& This stwl/ in mode pmitble through s (rant : from the QutUs Atbestns Mining Asyeauau. Medical Dircclur fDr. Oraon) and Statistictl Ceuiuhaut (Mr. Truan). Industrial Hygiene whose work is also, frequently referred to as establishing a connection between asbes tosis and oncer of the lung, reported in 1951 that cancer of the hmg waa present in 14.1% of asbestosis cases examined by him. In 1941, Tfordmam and Sorgcra claimed to have produced hmg cancer in mice which they exposed to asbestos dust. Since 19JL additional cases of cancer of the lung coexisting with asbestosis have been reported, and, according to Huq*r u about 10C such cases had been reported up to 1955. As a result, an association between the two diseases appears to have been ac cepted by many authors, and several writers were using the term "asbestosis cancer" of the lung. Werber," in 1952, stated categorically that in 7% to 17% of cases of asbestosis, after a blent period of about lyi to 20 years, carcinoma becomes estab lished in the lung. . On the other hand, not all authors ac cepted this alleged association without reservation. Saupc" hi 1939 reported that he had discovered no cases of lung cancer among 620 cases of asbestosis which he had examined; and in 1942, Hollcb and AngrUt'* expressed the opinion that the number of cases of asbestosis with lung cancer was too smalt for statistical tvalualion- In 1947, Wegdros" reported 126 tadiologiciUy diagnosed cases of asbestosis among 476 workers in Finland, and. found no cases of lung cancer in this group, (toldbbtt and Goldblau in their section of Merevether's blest book,** state: "But at no stage in all these impressive researches was any due obtained which might have offered any supjiort to the possibility that arhestes enild act as : ci. .1- ... . 614 1 /*/jO 3a/Xi---- / "//Vty V IMKC CANCER IN ASBESTOS MINERS it KW reliable criK-riiol b)' which one calk anticipate arcinugvuicii) and. at is wdl known, relatively minute changes in the structure ol a chemical careittegen are suffi cient to dimmish or eliminate ctrdnugeuic "scheduled" areas, by which is meant, "those areas where processes arc carried on which Were scheduled under the Asbestos Industry Regulations of 1931 as being dusty.** . action. There is, funttennurc. a complete lack I ( asbestos it iinleed to be regarded as a carcinogen, the need it fdt to demonstrate some property which cut be regarded as something more than inertness.** These authors advance the theory that, until some more experimental evidence of direct carcinogenesis by asbestos or a decumiositUm product of it can bo obtained, asbestos might be considered as a "co-car cinogen" which only induces a further de velopment of a preneoplaslic condition ''' brought about by something independent of the asbestos, such as an endogenous faemr. Thus the literature, while tending in sujpnn the thesis that asbestosis is in some way related to the development of lung oncer, is by no means unanimous.. Alto ' gether, it is perhaps more confusing than enlightening. A oreful review shows that the majority of the reports are clinical and not epidemiological. They lack many ele-' ments necessary for the application of epidemiologicd teduiiques to their content, and most of the authors do oot make claim to having done so. What has happened is that succeeding authors have drawn conclu sions and generalised beyond (he scope of the works which they quote. Nowhere, for of definition of terms as used in the pub lished literature. For example, the term `'asbestosis.*' as used, may refer to changes observable only by microscopic examination ol the lung tissue, or it may mean a radio logically detectable condition. Most of the published reports obviously included women sntong their cases, but seine of them do not give the number or pro)tortion of women involved in the study. There is also a lack of tmifnnnity as to whxt type of exposure most studies have draft with. Of 99 cases enumerated by Hnejier** in 1955, mlv 10 appear to have originated in the United Stales, and 7 in Canaria. Some of the earlier reports ap parently included asbestos miners, but it can be' assumed, since 82 of the 99 cases had originated in England, and since no asbestos mining operations are carried an in that country, that most of the reported eases have involved workers in the textile or fabricating industries. Such factors as smoking habits, family history of cancer, length of time in the industty, and age of the individual ease are also notably absent in the majority of these reports. example, have we found references to population of asbestos workers, although several authors who have quoted the ob served incidence of hing cancer in autopsies of persons who aljo haif.ajbtiloni imply that this incidence applies to asbestos work ers, generally. We have likewise been With' this understanding of the limitaIrons of the existing literature with respect to epidemiologfatl generalisation, it may be nf value to consider in somewhat more de tail some representative earlier publications, a few of which were referred to briefly above. unable to find any study which actually calculated the incidence of lung cancer among a population of persons who had asbestosis, and not just those who oune to ' ' autopsy. With the exception of n taper V *VI,M none of those reviewed five any data oil exposure and dust concentrations, and cveu Doll's paper merely mentions One of the most detailed studies and one which deserves the most serious considera tion is that reported by Doll" in 1955. This study reviews causes of death among asbestos workers based on coroners' roc- unis. It abti allkitip!.. i,. uk iimc In- studying records ol men who worked for at least 20 years in exposed situations. Prow--Tniw /V 61$ w A. U. .4. AftUIII'llS CM' IXItrSTMlM. HK.4I.TII IJutl concluded that hmj cancer era* a spe lung cancer in tuber (urms of pneunwvconkj- cific industrial hazard c( certain aibestos sis ryas (L7Si. and in 109 cases which workers and that, after 20 year* of expo- proved not to hare any type of pneumo rare, the risk U 10 timet at great at for coniosis it was 8.35c. Gloyne considered the general population. "the mortality of the asbestos wotkers" to This article it important fur several rea sons. in addition to the definite conclusions at which it arrives. For example, it begins by stating that "in view of the infrequency of asbesiosis, this large number ol cases f61 oscs of hmg cancer) suggests--but does not prove--that lung cancer is an occupational hazard of asbestos workers." Neither this article nor any previous one which we lave examined presents any fig ures to prove that asbesiosis is an mfretprent occurrence. Estimates of the number of persons potentially exposed to asbestos dust .in the 'United Slates alone ran- from 10.000 to 35.000, and the incidence of asbestosis of any degree might be higher than be "disturbing." First of all, it is obvious that the paper does not deal with the "mor tality of asbestos workers." and secondly, it must be borne in mind that all of Dr. Gimme's cases were submitted to him for study because the findings were unusual for uncomplicated pneumoconiosis. It can reasonably be assumed that cases, including those of asbesiosis. in which the findings were not considered unusual were ttnt sent to Dr. Gloyne for examination. As a nut ter of fact, hi the_ same paragratdt in which he expresses concern over the incidence rate in asbesiosis. Dr. Gloyne himself imams out that the rate (or lung cancer based on necropsies at the London Chest Doll imagines. - Hospital was 2Ufo while the figures of This study. Hitt so many others, involves autopsy records The number of persons involved in the statistical analysis >> only 113, representing only 1.042.25 man-years of fife. It is also true that in selecting men who had been employed for at least 2U years, the study automatically excluded the Registrar-General showed only 2.4$c. He thus recognised that autopsies on a cer tain selected group of cases were nut reprcscntatice of the general population. It would arcin. then, that notwithstanding the value nf Dr. GInvite's work, its importance as an Index a( the prevalence of lung can those who died from other causes after cer in asbestotics has been mtsmlcrpreted shorter employment. by some who have quoted him. A0 that it Another reason why this publication is of importance is a statement which it con tains to the effect (hat "the. strongest evi dence that it (lung canter) may be a hazard fin asbestos workers) has been produced by Mercwcthcr and by Gloync." In 1951' Gloyncpresented a. review of 1205 autopsies on persons who had worked in various dusty occupations. This number included 132 asbestos workers, nf whore 121 showed "prseamoctmiosis"--pre really shows is the fact that in a group ol 121 cases, selected for special study pri marily because they seemed abnormal by preliminary examination. 17. nr l-t.Kc, had hmg cancer. McrewethrT in 1947. in the rvport of the Chief Inspector of Factories, reviewed aH cases rc|vmed between 1924 and 1946 in which asbesiosis was the cause nf death ' or a coexisting condition. This work was bier extended to include all such cues re sumably asbesiosis. Primary cancer of the ported up to December. 1954. by which time lung.occurred 17 rimes in this group, an these were 344 deaths, including 205 males inojfcnoe rate of Kl|t for hmg Cancer and 139 females. Among them were 55 among asbesiosis cases coming to aatofty. uses (IW) of cancer of the lung, 41 in There were in his scries 796 cases with sifi- males and 14 in females. It is ipiite |ossible ----a 6.9 of these also showed pri that a Urge number nf stVewk. vtw -tot mary cancer of the lung. The incidence of not die nf their asbesiosis. or in whose 6J6 . '/. IT. Jm. Ii AV LCSC CANCER /.V ASBESTOS MINERS doth certificate it was Rot mentioned. mar prior to that date and enumerated a tout hare btm inured. The import ol this ' of 99. Eleven of these were those dis is enhanced by the simultaneous statement cussed by Doll** and may have been cases that the tnciilencc o( King cancer in autop covered by other authors. Eight were dis sies of the general |io(nilaiioo is only 1%. covered by Kcnnsway and Kennaway ** in The danger of attempting to compare a an analysis of death certificates, knd. unless rate found in W cues with the rate for Mcrewether's study was incomplete, these the general population without respect to cases should have been included in his re age, occupation, and many other variables, port. 'Of the remaining 80, it is quite pos such as smoking habits, is obvious. sible that the 31 contributed by Merewethcr Lynch." who with Smith** had reported the first case in 193S. reported 4 eases of carcinoma of the lung m a series of 49 and the 17 by Gloyne contain some duplica tion with each other or with those of other English authors. autopsies on workers in an asbestos manu facturing plant who were shown to have 'demonstrable deposits of asbestos in the Principles of the Epidemiological Method lungs." This, of course, is not necessarily identical with the disease asbestosts. Lynch, hintseli. points out. that, although this is an incidence of 82%, "both figures are loo Dorn * has pointed out that much of what is now thought to be pertinent concerning the comparative -frequency of lung cancer in different population groups has been de small for very serious statistical types of . veloped from die analysis of clinical ma calculation." Nevertheless, later writers terial. particularly surgical and autopsy have used this paper to strengthen the case records, supplemented to some extent by for an association of carcinoma of the lung the reported impressions of various efini- with asbestosis. It is also of interest that Klott ** found only the same number of cases of tong cancer in a tenet nearly 10 times as targe. I -e., 4 in 478 esses- of asbettosis. cians based upon their personal observa tions. More recently, however, attention has turned to the systematic Investiga tion of this problem by the same methods that have proved so successful previously in Behrens, as cited by Merewethcresti the study of communicable diseases, that is mated that, of 309 cases of asbettosis in the to say. by epidemiological methods. literature, 44 showed associated cancer of the lung--giving an incidence of 142%. This is an illustration of generalizing an inetdeme.obtained, in. a group of cases which were undoubtedly reported only he* In order to apply this method of investi gation to the problem under discussion, we were of the opinion that a study should be planned to as to provide (I) a well-defined population group; (2) available data for all costu some of them showed lung cancer, to members of this population, including the possibly hundreds of asbestoties whose healthy as well as the ill; (3) a sample cases were never reported. The same ap plies to the conclusion of. Teleky.** who appears to have reviewed reports of 39 autopsies on persons with asbettosis among which 6 cases of lung cancer occurred. In formation from sources such as these docs not justify generalizations with regard to mortality rates. . which is truly representative of the popula tion; (4) reliable and valid observations relating to the problem of the study. A serious defect, common to most of the studies which have been reported, b that Ettle or no information concerning the healthy people in the group seems to have been available to the author. In order to Perhaps no one has written so exten- draw a generalization regarding all asbestos snrelv on the subject as has Hueper.**'** workers, it is necessary for a study to in In 3955 he reviewed the cases** reported clude living persons as well as the dead. BrU*--Trttcn A. U. A. ARCHIVES OF WOUSTRI.4L Hh.it.TH Limiting the investigation to cases coming be found in another group of the same size, to eutffiy, as has been frequently done in bin representative of the general population. earlier studies, still lurther restricts its use It is true that investigation of cases from in generalization. The problem with which such a sample can furnish information we are concerned is whether asbestos valuable for research, but the use of this miners experience more lung cancer than information in drawing generalizations is does the general population. The answer necessarily restricted, ft is the obligation necessitates the collection of reliable infor of both the investigator and of those who mation on asbestos miners as a group, as read his report to make proper comparisons well as on the general population. and to draw only those conclusions which It scents advisable to discuss the differ are valid and justified. A good statistical ences between the epidemiological approach study of cases of cancer of the hutg occur and that toed in the studies which have ring in a group uf autopsies can lead to a been reported to date. - A very important proper inference concerning (he frequency consideration is the fact that long cancer, of lung cancer among cases coming to in spite of its increasing numbers, is stiU a . autopsy, but only to socb cases. For in disease of low incidence; that is, in a given formation from such a study to be pro population not many persons will centric:' -jetted ta jomdirger group, it isTieccssary this particular disease. This fan requires that the autopsies represent a good sample that large samples or groups must be stud cl that larger group To assume that soeh ied to provide meaningful results. is the case in any particular series is dan Recognizing the difficulty of obtaining gerous and likely to be false. such large samples, most earlier writers There it some danger that the figures deviated from the epidemiological method reported by some juthors may be miscon and sought to circumvent the requirement strued as applying to asbestos workers or of observing well persons by (I) compar even asbestos miners, when, in fact, (he ing the rrlcihv frequency of cancer in vari authors in question do not make this gen ous 'sites: (2) comparing the reiative eralization. nor can the generalization be frequency of cancer in a group of hospital nude for the reasons staled. Close study of ized patients; (3) comparing the relative the reports reveals that the percentages frequency of cancer in a group of cases cited relate only to the group of autoppes coming to autopsy. covered by the particular investigation. Attempting to compare tw<> leqnitation .groups. Inditing only at the relative fre quency of canter in various body sites, may result in finding a higher percentage frelative frequency) in one of the groups, when, in fact, the mertetity rate of cancer at a particular organ is exactly the same The present study, in contrast to the earlier works, has been planned to utilize the epidemiological method. A well-defined group of asbestos miners has been estab lished in such a war that ic constitutes a guod sample of the whole population uf asbrsth* miners in Quebec. Data for all in both groups. This is- very clearly dem members or this group have been collected ons:rated in the excellent article by Dora* anil analyzed. Those concerning hmg can The 'mortality rate from a particular cause ter have received most careful considcra- ' is the Trite measure of comparison. - tiotir Details of the methods employed win he set forth bier, but the type of ajiproach It is apparent char selected groups such is considered to. permit of fair comparisons **' hospitalized patients or autopsy cases and valid generalizations. may not be in any way representative of a larger group, and chu in dealing with Collection and Analysis of Data such samples, the observer may easily find A preHminair survey c! wuiccs --- cases_pf (..given disease.than would uf information in Ftbruaty, 1956, involved &3S .................................. Vet. 17. /. W* /W S'cfj. U'.W i'AXCKR IX .4SHHSTIIS MIXliKS diacussiun* with the ph}'(ckui> in charge enhon wa* then inlluwcd by meana of the of the asbestos cunqsutics' progecutK atul annual (>hv<*cal examination records with cfinicinnj. |iAthologi>.is. re|>re*eiit.nivr through a six-year interval, 1950 through of City and Provincial health deiartnwnt'1 1953. All data regarding this group were and of the Canadian Cancer Swirly. and then tabulated in order to determine the ither interested |*t*uii. Jt w fuuml that characteristics of the cohort. For those who morbidity data, although sntncwhai limited, survived the enlist jwriod. reference was were available." from nich stances n the made -:o the physical examination results hospitals in Montreal and Quebec City, and and x-ray findings at the end of the period. the 13 canter detection centers in the I'rov- Those who had died were tabulated sepa ince. However. because of' the high mor rately. and the cause of death was tality in hmg cancer, it scorned advisable corroborated by examination'of the death In de|iCTKl ojcai data relating to deaths. certificates. A further search was made These we found to la* obtainable at the concerning those in the original cohort who vital Statistics department of the Miuistry retrained unaccounted for when the living if Health in Quebec City. Fnan the pre- and the known dead had been tabulated. limiturv survey, it n a|*]vtrrm that eaten- Pier represent men who had left employ sice and detailed information cmiM he ment through retirement or resignation. gathered with respect to both the |<mi> Kvenuuily. all but a small number of these employed in the asbestos mining industry were accounted for as either living or dead, and the mortality figures for the gntcral and in the buer event, the cause of death 1'ipuUlitMi. ' was substantiated in a similar manner, and ` Following this cxpltiratnry survej-. the the results added tn the original list of initial effort was directed to the collection deaths. of data rtiatmg to all workers who had Death certificates for the Province of been processed through the clinic at Thet- Quebec for the years 1932 to t935, inclu ford Mines since its inception in 1947. and sive, were reviewed in the department of similar information regarding all workers vital statistics of the Provincial Heahh ar Asbestos. Que. Data from the clinical Ministry, together with statistical sum records induded the age. family ami per maries of the causes of deaths in the Prov sonal medical histories, smoking habits, ince by counties.' All cases in which death number of years of ex|Kure. an estimate was certified as having been due to pri tf weighted exposure, .-ual the course of mary cancer of the lung were examined for the individual's health status nr the cause such information as place of residence, of his death. ' " ' occupation, date of death, hospital in which From this infonrutioii it was pnrsible death occurred, and whether or not an to formuhut a "cohort" which could hit well - defined, should be representative o.f the whole group.-and could be followed for a autopsy was performed. Cases in which lung cancer was given as a cause of death, but in which, it was not specified as to definite period of time. AH of the available . whether the cancer originated in the lung, experience' indicates that .the devetopmeut were also reviewed in an effort to include of asbestosis is less than five years of ex all instances of primary carcinoma of the posure must be somewhat rare. Accord lung in the study. ingly, the cohort was defined as including The statistics for (he Province of Quebec everyminer who had.ajoUl.cxpnsyre of relate to population, tout deaths .from all five or mote years, and who was on' the causes, total-deaths from cancer of employment rolls in 1930. Office and other and deaths from hmg cancer. These were nonexposed personnel, regardless of length collected and tabulated by counties and by of employment, were not included. This MX for the years 1930 to 1933. inclusive. Bntm--Tnam 6 /*/ U. .1 AKCUirFJt Of I.VDCSTKI.1L Ht.1l.ru From them, death nin for the pocnl population of Quebec and of individual counties were calculated for specific years and analysed by cause. Practically all employees of one company are covered by a group policy of life insur ance which, fortunately, nearly all of them continue to cany when they retire. A very few are not covered by this policy, and those who leave the industry for one reason or another except retirement usually arc no longer covered, hot this is likewise a small number. As an additional check upon the information obtained from the clinical records on this group, _the records of the life insurance company were examined for all death claims paid under the policy, and particular notice was taken of the claims in which the proof ot death was based on' cancer of the lung. lit addition to this analysis of deaths oc curring in the cohort and during the years under observation, every known death from cancer of the lung, as well as every case diagnosed but still living, has been tabulated and analyaed. They will be discussed separ ately from those included in the population and tone-interval under study. A comparison of lung cancer mortality in the asbestos-producing counties has been nude with that in counties which arc far removed from the asbestos mines and in which, presumably, no asbestos miners live. Finally, in order to broaden the compari son nf doth rates in different population groups, the rates have been collected for Canada generally, and for the United Stater, according io. the mot; recent published and unpublished material. Deaths from lung cancer among asbestos miners were thus determined from the clinical records in the medical service of the industry and checked by means of the death certificates and insurance company records. The deaths were then verified individually by reviewing them with the physicians in charge of the medical services. In this man ner, there was established a list of cases in which primary cancer of the lung is con sidered to have been proved as the cause of death. A few cues in which lung cancer is strongly suspected but not proved ay the cause of death were considered separately. Mortality rates have been calculated using both the "proved" and the tosil of "proved" and "suspected" cases during the years un der observation. ' Comparisons were then made between the death rales fram the same cause among specific seginerits of tmexjioscd persons. AS lung cancer ' deaths, both suspected and proved, were carefully ana lyzed to determine possible relationship or correlations between the dtvelo|iment of lung cancer and any factor known front the clinical records, such as family history of cancer. |>ersoaI history of heavy smoking. wsAisntict ot asbestosis. Or exposure In asbestos. Results and Interpretation The cohort which was constructed accord ing to the criteria described in the preceding section has been considered individually and compared with the general population. Description oi the cohort will be presented here as s preface to the resells of the study: Original C*to*i Lm fiinrM tKJwgiiJ fMii C*rt * Liwiev In |fSS M*l Wtitld) Ik* fcr rtH ' Co** tone . qnllwnUl tMRf y barf Odwr iMin I'BfcrfMT* gttitgt . toUtn %'m*m - ` - rtwo>p . Mil IJ) MM un w t .i 149 4 MU UJ JO Tables 1.2.- 3, aml.d present age. number o.f years of employment, weighted average cxiassure, and smoking habits of (hr cohort. . A cntrtpariMni of the exposure to asbestos dust is presented in Table 3. All members nf (he cohort were placed in one of three categories, representing increasing degrees nf exposure based m a weighted average <if the years s|nt at various levels of lustiness. The degree of dustiness for each job category was determined after re-'"'". two with persons familiar with the environ- ' mem and conditions in the various work *K> iv. n, tu,f. tvs* Av -- - '--- *.A- Ji %** LVSC CANCER IN ASBESTOS MINERS T*m I.--Nnmbrr md PcrtmtoOf Visrtibonoo ________________by Aft a dms ____*.................. ............ .Vradr J-*ct 1.12* 11 U J AMI 41 Tabu Z--.V*--V- Pmrrtoge Dittriboiiom by . Lnqlk 0/ Emyloymtml *kalmui. areas. For the purpose* of calculation, the assumption has been made that the relation ship between these categories is linear, and that Category II is twice as dust}*, and Category ill three times as dotty as Cate-' gory I. ually smoking more than five cigarettei per day. Persons who smoke pipci or cigars exclusively were not considered to be smok ers (or the purpose of this study. Table S presents the yea--by-year ex perience of the cohort and indicates the Taste J.--Numbfr o*d Ptrtmiogt DUtrlbotioo by Eryotorf Caxtgory Tabu t.--Svm*br* Ood Prrrentaqf 0utr$anon by IiMtiay Hobui twviTLwipo-t-c-n--_- _---__.._.._...._.._.._.._... MuoU UattaoSan. . WO ontiai iucru MfnmnSM.,.,,----OotMVt.^.___ Tt*u*v- -------- --------- - Hoax* U3 UU 39 UU 'kaOusrt. Pa Cot if ts MO The fourth variable, smoking habits, was similarly tabulated and is shown in Table 4. This was included because the informa tion was available and because smoking was regarded as one of the variables which, besides the environment, could conceivably influence (be development of lung cancer. As used in this presentation, the term smoker refers to a cigarette smoker, habit- number of deaths each year from specified causes. In general, a case was considered to be `'proved" as one of primary cancer of the lung when the records showed that the diagnosis had been supported by an autopsy or surgical resection of the lung with microscopic examination of the re moved tissue. In one case so considered, however, diagnosis was confirmed by bron- . Tabu 1--Ytor-by-Ytor Ejperlmr of Cohort and Drath RaHs for 100POO '* Man-Yean of Risk . fo. AHAt lUtIBVM W Vw Itn------- .---- LAI iro______li.________ mr____"............ UM____________ us uu UlS mk UDX09 w yein af r* 1C8JU81 rniry I 0t I I I ~i nso '* t-n Oki(U*( sz Jo X S9 X KmA'm US iuxnu ttsu /V O A. it. A. ARCHIVES OF IXDl'STRUL HEAl.TH t Tollx t--Vrawrf" Can of Primary Confer at lie Long Cam No. I ti l Aft att u M ftl M C u Saota Yu Ya Ym Ya $S Ya Ya Ya Ccpomv 2ftTT.tsCl.lt KTt.mCu.1 Hyi.MCtt.1 SSSStii. 20 It. mCu.lt l|T.O CU 1 art. is Co. in D*t4 !9-T>U ft- fttf ft-J0-30 -II aft- -M loMpir Ytt Nvo Ya Ya Ya Ya Ya Btoaft. AiMim Ya Nt So No Ya Ya Ya No No choscepy with visualization and biopsy. Ill would be very close to the 95^ level another, although there was no autopsy, the of significance. However, having found just diagnosis of primary cancer of the lung 12 cases, wc are not above this level, and seems to have been beyond question. therefore the hypothesis that asbestos miners The terns "suspected" primary cancer o! do not have a higher mortality from lung the lung was applied to those cases in cancer than does the general population can which .the diagnosis remains in doubt but not be rejected. Nevertheless, the occur some of the evidence points to cancer of the ' renee of 12 cases in this sample would lung. There were three such cases. ,, increase the rate to a point which approaches The term "man-years of risk" has been the significant ieveL Because of the tre used to mean the number of men at risk mendous importance of the questionable for the year under observation. A person eases in this respect, some detail regarding who lived throughout the year was counted them will be given here. as a full man-year of risk, bot one who died fit vine of these eases, the suspicion of during the year was counted as one-half a cancer of the lung is based upon the x-ray man-year. interpretation, and. although no autopsy was Oaths occurring in the cohort, and in performed, the death certificate indicates which lung cancer is considered to have that death was due to lung cancer. It is been proved as a cause, are shown in Table well known that the x-ray appearance of 6. In Table 7 are shown three deaths which fibrosis, especially if a localized density or have been considered as "suspected" lung a superimposed tuberculous lesion is pres cancer cases. ent, can simulate that of a tumor, and by An indication of the importance of these itself, does nut justify the inclusion of this "suspected" cases in interpreting the results case as one of "proved" canter of the of the calculations is desirable before fur lung. A second case was certified as haring ther discussion of the mortality rales which died by reason of hydrothorax, possibly due are derived in later tables. For example, it to lung cancer, but again there was no happens that the rate found for the proved surgcTV and no postmortem examination. cases is dose to the "expected" rale based In the third case, although it was subjected on the general population figures for the to autopsy, two pathologists disagreed as to Province, as will be shown later, and on whether lung cancer was present. The death this hosts we should find eight deaths from was certified as having been due to chronic lung cancer among the cohort. ActuaHy, myocarditis with nephritis and pulmonary nine cases were observed. If, however, the congestion, and possibly canter of the lung. 3 additional "suspected" cases were in On the basis of these farts, it seems unwar . chided, increasing this figure to 12, the total ranted to include these three cases among Tails 7.--"Sajtrettdr Primary Ccnftr at tit Lmg Cmr M*. I 1 an m s tart" Ya Y Ya 37:-St Sit ar<n Cot u No Yet Ho Ho 641 Vet. l?t Jmr. JOit U \V<; CAXCti* iX JSBlLSTns' MtXr.RS w|wvdM iusUitco of hmg cuwrr. On the 4her fund, they cannot, tn famc>. be tlisrcganled completely. It i* fur this' reason that mortalitv rates have been catrutaietl l*4h ways. Table 6 give* the rates by age gnm|*. < The rates by length of employment arc shown tn Table 9. During the first 40 years if employment, the rate rises, an observa tion which seems plausible since the men were growing older. However, after 40 years of exposure there are no "'proved" rases reported for a total of 240 men dur ing the six years, or about 1440 man-years of exposure. When the Msus]ieeted" cases are added, one case does show up in this TfttoX 6---Conffr DfCtit fry Ayt Grvmft Ta(U *--Lm*$ C'enrrr Oralhi fry L*"*gtk t*f Emphr)wml r t < KUwwjWhi|oiaf(ixt M........ . W-W*......................... mi Un Cwr OiiO* . K^dtWtltt tfM. AM|1 Um (WlUi lun pn 100.000 HwVwrt mi KapoMf* Enpiifmiin ao-*-*n..^....^................ m.............. ..... TfMl 0 I 0: M m0o u Swf mi Per wt ml ?>iWr f Unc rWMki * N.ml - Sm. |mM AC* ' 1`vknk l*roiw rmti J0-M................. U-M.............. . U-*.............. .................. ... __ _ it% 1 i4 V i * i 1 TMb. .... *.* 1 n AsmoiI Vjm Cmh One* Rft Mt lOOlOOT Att imp -*................. (KM................. ................ ......... hvii 1 u M 9na e Tul fci )U * |iul. Thiji itimW |mxlurc a rate of 69 |<ct 100.000. again demonstrating the imlnancc of (hoc questionable. bol un ' prmed. case* to the final conclusion, tonus?, if there were no easts in this number of men with long exposure, and if asbestos is a carcinogenic agent, it must be ' concluded that these Z<0 men have demon strated considerable resistance. This is a bio - logical phenomenon which has been observed previously and is consistent with the theory ' of an intrinsic or endogenous factor in can cer. The only other explanation would be that the susceptible members ol this age group had died earlier ol lung cancer. Table 1R. which appears later in this sertirm. in frrMaw.TpMii dicates that the members of the cohort did not die from lung cancer at a younger age than the general population. The rates by weighted exposure are shown in Table 10, and it will be noted that they present strong evidence against asbestos toing a carcinogenic agent, lor. ii exposure to asbestos is in any way con nected to lung cancer, we would expect that the longer and heavier the exposure, the higher the rate that would to found. The only possible error in this interpretation could occur if the weighted exposures were inversely related to years of employment. 10.--t'rv.r Dralht by F.zfomrr '* ' CattQory NavVf ( ftnkt id XmwWt *4 Umi Ciwh brnlit f.lIWUPI Cttctorr V.f tain hind T*vu 11..,.,,..TM. .. . Ill........................ VMmviu...... .... Tam___.... 14J0 1^1 > U* i 0 f it Aeiwil Ijp( Cwrt Dtiifc litn nr MnrVan mi Cisain 109.000 Citnsn Camry li ................... ............................ Ill...................... Ufttaour*_______ ~...................... Orff40... PfffcO M % si Tm P It M 60 f*/ A, U. A. ARCWVIS OF INDUSTRIAL HLALTH Tiur 11.--.Vm&rr of Pt^tomi in V*riot Weighted Eafcsmr CoUgonee bf Length of Bmgioynmt M**rd limgrr 4 a in kn**i Tai set U a10i *o Ul ( tumm tt*+ lu vno M 0 M IT 41 * 9 ( % 0 V9 U tbub SA1 luo vm 4m pan Rl Ri Ml * Msi 90 Tacu li-ttoif Confer Qto/h for ' fmokrn m ffonemohrro Ni4s if Pimm 4 Novhr A Unf CiMtr tlwki Vy imomm Him* Final ........... i.n Nomwun-ww,... vsto T***_.. MSS fnnS t 0 0 "t Tsoi 4 n ARaul ton* Csmr Owl Asm Mr 100,000 Xn-Von f ttnwn *r S--Hibu in which ate the heaviest weighted ex posure (Category 111) would show the shortest length of employment. Table II, which lists the number of persons in various exposure categories by length of employ, mens indicates that this error has not oc curred. In fact, the average number of years of employment for each exposure category is almost identical. Table 12, which develops the rates for smokers and nonsmokers, is most striking. It shows that not a single case of lung cancer developed among the 1265 non smokers and that all cases of lung cancer, both "proved" and "suspected." occurred in smokers. Table 12 was so striking that it was felt that further verification was necessary. It was possible that some abnormal distribu tion may have occurred, e. g., the non- TablC 11--ffumbrr amd Prrtmtogg Distribution of Smokers ond Xousmobers by Age Ceouys AseCeooo -Keaber Sorter Xooowtrr Cfttar** tn snen i*tau O_____ . Snetm._--..................... Xnunwrc.................................... O-oel!______ Tul a imokers nay have included a larger percentage of young men. Consequently, ad ditional Tables. 15. 14. and 15 were con structed to show the distribution of smokers and nonsmokers by age. length of employ ment, and degree of exposure. Although there are slight differences, they do not account for the fan that all observed cases of lung cancer were in smokers. In respect to age (Table 15) the combined average age of the smokers was 4.9 years less than that of the nonsmokers Table 14-shows that as far as length of employment is con- Taota IS--.Vwohrr ond frrrnvcr Distribution of Sotokeet c*d Xonemokers by Length _____________ Of Emflorment____________ .IrMib 4 CapwrmM M................ to-ii............................ p-ii..................... .......................... ____ Xeaavr Irntm Xiiiihiwm MunMt n m41 JmT? in Wn T in MO XT* l*J Ctnwq 10 j o . t so 10.0 hmtttn OUfttMton am Onep taster KlMMtW U-H....... O9M.K_--___.W__W_W__W_._.. U IMU u Ml i;1U ill 90 uea Colon-- Ml 9XD tstoo iooft * l*a niftdQ%. 644 FirniMW OlRittnM tiMittf teptey--bi H-w................-- ...w ... tnnno --Tiottw. r<MM>U m 91 IM IM Ul S.T 11 w% fnlfitvB Ml 01 104 90 Vol. tf, Jmnto J9U Sa, LUNG CANCER IN ASBESTOS MINERS Ta IS,--Nombrr and PrretnUft DUtriSottoo of Smohert end Nommoltert by ______ Ewnn Coutort. IN u> aI a u SunS? , rworgan Dbefenbe Imoi SwaNii Vakaoaq _______ U _________ IU _ aj ....____ M t>ui>_____ non 5.1 nj U twf. M M -<u U im% earned, the smokers had worked about 2J years leu on the average than the ndnunokers. With longer exposure and greater age, one would expea the nonsmoking group to show a higher rate if lung canter were due to asbestos. Table la shows that the average exposure category was almost the same for the two groups. Therefore, this variable stems to be of no importance in accounting for this difference. The result of this additional analysis is that none of these factors appears to lessen the effect of Table 12. Comparison of the Cohort Experience unth that of tkt Province of Quebec, Do minion of Canada, and the United States-- In order to make a comparison of the experience among asbestos miners with that of the general population of the Province of Quebec, statistics were gathered, as stated earlier, in the office of the Division of Demography in the Provincial Ministry of Health. The data an total deaths, deaths from all forms of cancer, and deaths front Cancer of the lung were obtained by sex and-by county for the years 1930 through 1933. In addition, all death certificates which specified primary cancer o( the lung, and ill those which indicated lung cancer but did not specify the origin, were exam ined for the years 1952 through 1955. Table 16 gives a tabulation of the number of deaths from lung cancer in the Province and in the cohort for the years 1950 through 1953, and shows the annual rate per 100,000 in these segments. It win be noted from the table that the mortality rate for the "proved'' cases in the cohort is only slightlv higher than the rate for the Province. When the "suspected" cases are included in the calculation, the rate for the cohort rises to 33.8 per 100.000, which is about 505c higher than the rate for the Province. This, it will be recalled from the previous dis cussion of the effect of the "suspected" cases on the results, approaches but does not exceed the significant level. One further interesting observation from Table 16 is the rather marked increase in the total number of cases for the Province between 1930 and 1953. It is assumed that at least part of this increase b due to im proved recognition and icporting of lung cancer during the interval. For thb reason, the years 1954 and 1955 were thought to be snore nearly representative of actual condi tions. Even so. it is quite likely that the general population is not studied for lung cancer with the same diligence with which Taste 16.--Comparison of Cohort with Proobtee of Ombre Tsui mm tiJu vwloas Solti Naatartf ftnaw tsa ml t*a ua m* > RMtetT ms T*"* An 109.030 m as to SO ' sss m M* uat toIM s\ us s ..j )t > IS % m9 i BS t9 SM Utt rj tu a ta ts SNNM BIMIIubmiaawtiOaililMaaqrlwhtiitb. QMS o. - iw. SKNttaM nnoooo f in* acvsramad papNUM Sal INCtfSlUfOiaMid pasv|ln-- W ISM (SappMV Dtv. Sa to tkt. lOffbfftff la tXttie&ar alivt ts Mart at baraMac at ISSL Troon 63 Ai/ /- o Jkf CfMl 20-M **.* U-M *4+ TfUb A. M. A. ARCHIVES OF INDUSTRIAL HEALTH TaiU 17^-iaftp Cater Deaths far the Protest ef Qmshee* 1 _ i i ' SomOw if Distil tu ' tU9 twim>u< t lopiimi n7XjxOnB I4M UlM 131400 TmlCWttih TmI fwagj IT Mn to# 14 IU 44 tt S#K*A*di *r* Tvcal rmit 11 1) a Ma a9 mm Tool CcniM TuJ nwit 9 aa UT 39 Ml It 90 m fwci4>f1 frffur T*ut /mid 17 m ia M m JUi 0*#P . .. . -----*...________............................. 0W4IUm>-- Butt bw fet 160.00# m IteiCMiiStt IhoAh fraowy T*u| rmit Tint hh*n rs 1.9 l i* *nBus4 114 n.i 99J 9LX 00.1 964 n.i ai *4 aj tj 134 14 ttu TtoftlCtfUM IOWMi frxfi TmI 13 *1 1L4 1=4 rn*H 14 1*4 4U Ml TOttl 14 3T4 *.t 1=4 fnt 19 194 l.l <a 394 113 334 hi *f tDo*tnSxfc*lB!Ttm*! oi*<*3 *r *991909 WH tiwimw toe t|i c^ea tar atfct ta Ut i#ol otpslitM it HM. w uni (a fcippan. 0t*. :i u Oroapapo*, this disease is looked lor in Ox miners, tnd it seems probable thi the mortality rates (or the Province nay be tow. This would appear to be sabttantiated by the (act that the reporting of cases in the cohort showed no such increase over the same period. Table 17 was compiled to show the an nual age-specific lung cancer rate of cases in which the doth certificate merely read "cancer of the lung." as distinguished from those in which the diagnosis was confirmed by autopsy, surgery, or biopsy*. The term "specified primary" refers to those cases in these two categories in which the tumor was specified as having originated in the long. It will be noted that, of the total cases reported in 1955. a modi higher percentage than in !9S< were specified asprimary. The table also shows that a higher percentage of the total cates certified in 1955 were proved, again indicating increasing interest in this disease. A comparison has been made between the age-specific rates shown in Table 17, and those for the cohort, shown in Table & An average of the 1954 and 195S rates for the Province has been used, since the 1955 figure was higher and may have been ex cept ionaL This comparison, summarised in Table IS, shows that the observed number of deaths in our sample is not significantly greater than the expected number of deaths, based on the average ol the 1954 and 1955 figures for the Province. It is true that, in the ok ot the age group of 65 and over, the five deaths provide a figure which is almost significant at the 95% level. How ever, it should be noted that this number includes one of the suspected but unproved cases previously referred to. Furthermore, it is rather likely that the rate for the general population is understated in this age group, for the obvious reason that the exact ante of death in the very old is not Taste H.-CironiM of Ik Actual and f/piiri A'amdcr of Long Cenrrr Sulk try Agt dsw| dikifw ffhrri AM Oiwe tooirt <u* 14 90 U4 K*.# si.* Mm Dua` UH ot 1.1t*l HI It .-- 1 * Tto OMNd Mitn a tmwtf n tin * at (hi NM lot ItlS iKOMilt rt*c> tor (ft* Qmxc. UMMrh.i . Pet 17. font. r>St is It-.vc CAXCER IX ASBESTOS MIXERS Taslx 19---Act Distribuiiom of Admit klalrt for Tuu 30 --Amrnmol Droik Rout ftr K-0JKI0 tkt Provintt of Qmrbrtt 19)1 Comfrr of Ikr L**o w Canada * An fii9 ..... *H~~----------Tmri___ _ Nueacf 7lari.itun l&M MAM9* rwuun m no baton, tax. a miner of the same intensity of interest as it is in younger persons. Table 18 also answers a question pre viously raised. It shows that the members of the cohort have not died from lung can cer at an age earlier than the general popu lation, and that such an explanation cannot be offered ior the absence of lung cancer in 240 men with more than 40 years of employment referred to on page 643. ' Before leaving this comparison of the Province with the miners, it should be shown that their age distributions are rea sonably the same. That this is the case can be observed from Table 19. It should be remembered that die miners retire and consequently, it can be expected that the oldest age group will be larger in the general population. The data presented m Table 20 indicate that the lung cancer rale generally decreases alter age 70. There fore, we could expect the rate for all people over 63 to be smaller than the rate for the group between 65 and 75, which would apply to the oldest group of miners. It is felt that by using the whole adult male popula tion. we have developed rates for the gen eral population which are somewhat lower than if we had been able to exclude the people in the general population over 75. A comparison between the asbestos miners and the population of the Dominion as a whole was made, using statistical material from several sources, fn one source, Phil lipsTM gave age- and sex-specific rates for Canada for three periods between 1931 and 1952. The rates for males are given in Table 2a These figures show strikingly the increase in rates between 1931 and 1932. and this Am Ofp UwferP IK* 10-44 AQ Aft* *4 9J LA VI U . tut U.I tQ.7 tLA U l. tl Oww at Inn mw*u 04 Lt VI V4 194 1*4 . ft* ' SU *84 4 M4 T74 M4 U L0 Ut 1*1 P*4 a tt4 "Mmalff? Mm Lotts Csactr at Cswda.** Its* I* ItM* Increase is particularly marked after age SO. confirming an observation previously made, to the effect that until recently lung cancer has probably been underdiagnosed in the cider age groups in the general popu lation. To use these figures for purposes oi comparison, it is necessary to combine the rates for certain age groups in order to conform to the age distributions used in this Study. Since the exact populations in each age group for the years indicated is not known, this must be an approximation. However, the rates would be somewhat as follows: Alt Cm tit 1U** 31 t 00-9J These rates are, in general, lower than those dee-eloped for the total fproved and suspected) cases of lung cancer among the asbestos miners. The only large difference, however, is in the age group of 65 years and over, and it is quite possible that the rate for this group may have increased for Canada between 1952 and 1954 at it did for the Province of Quebec t'Table 17). A further comparison has been nude with an over-ad rate obtained from the American Cancer Society for respiratory cancer deaths in Canada in 1953. This rate, for males, is 20.S per 100,000. or } more per 100.CO0 than Phillips' 1950-1952 rate, and compares with 25.3 r-e. 1C2.C3C .V. proved cases and 33.8 per 100.000 for total eases among the W /. it. A. ARCHIVES Of tSOUSTRIAL HEALTH Taiu 21.--Xanther of Dtalkt and Death Rottl pet tOOi&l hy aof Grant* lor the Admit Mole Pmfmlotum of ike United Stetei * XtE GfmoO IVM TNfcl JOUM UMMt kCOlPB jStVJ30 Cittf o *.*.1 tUN ftsn per rtOrt) kUi kl no .l wtu* 0*14 tfo "Vtul ftrawiq A L4. Cabad tula," Vat I asbestos miners in this study. It is there fore obvious that there art no important differences between the rates for asbestos miners and those for the general population of Quebec and the Dominion of Canada.' Since it is probable that figures for the United States are more complete and, there fore, possibly more comparable to the data for the miners, age-specific rates were com puted from "Vital Statistics of the United States,* Volumes I and ff. for I93Z These rates have been tabulated in Table 21. It is apparent that these rates compare favorably with those for the asbestos miners as shown in Table 8. Still other rates for the Coiled Sutes were obtained Irons the American Cancer Society, and (or males, these were 23.3 per 100.000 in 1933, and 28.0 per 100.000 in 1933. They are not identical with the rate calculated from the figures of the office of Vital Statistics, but this is possibly because Che Ainericaa Can cer Society rates are (or males of all ages. Xevertheleii. they. too. compare favorably with the rates oi 23 for 3-1 (or total cases) obtaining among the asbestos miners. Turning (or a moment to a comparison between the asbestos mmett and persons who art exposed to asbestos in one form nr another fas distinguished from the gen eral population groups just discused. who base no exposure) an interesting observa tion can be developed by deduction. Hucper " has stated that there arc about 33,000 persons exposed m the United Sutes. and we have found that the Canadian mines employ about 8000. Elsewhere, it has been estimated that the workers in England who have exposure total between 3000 and S000. With workets in Africa, Denmaik, Nor 648 way, and other countries, at least 30.000 persons must be exposed throughout the world, and it can be assumed that this number has been fairly constant in the 20 yean since 1933 when the first case oi asbestosit with lung cancer was reported. At least 1.000.000 man-years of exposure has thus been accumulated, and this figure can be divided by the approximate)}' 330 cases of lung cancer with asbestosis re ported during the 20-year period. This gives a rate of 13 per IOOjOOO, which is at least indicative that any lung cancer rate which can be calculated for workers ex posed to asbestos dust is not much greater than that for the unexposed population. Comoariaon Benteen Eight Countiet Adjoeent to the Athettoi-producing Arear and -Eicht Selected Ccumin.---To compare lur.j cancer mortality rates in the counties sur rounding the asbestos-producing areas with another group of counties in which no as bestos miners are likely to reside, the rates were computed on the basis of figures for the years 1930 through 1953. The eight counties selected for comparison were Arfenteui). Chatcaugay. Montmagny. Portneuf, Richlieu. . Riviere-du-Lonp. St. Hyacinthe. and Terrebonne, mainly betause thes- represent a wide geographic distribu tion throughout the Province. The counties Selected because of their proximity to the asbestos mines include Arthabasks. Beauce. Drummond. Frontenac. Megantic. Rich mond. Sherbrooke, and Wolfe. Table 22 shows the number of lung cancer deaths for the tears 1930 through 1933 for each of these counties, and a mortality rate, based on the adult male population in 1952. To emphasise the comparison. Megantic County has been shown separately, as has the Province of Quebec and also the Prov ince with the eight 'asbestos-producing' counties subtracted. Became of its unique lung cancer death rate, Montreal et Isle de Jesus has also been listed in order to provide further comparison. ft is apparent .Vum tne table that the lung cancer death rate for the eight counties Vet. IT, J-me, SOU ' LCXC CASCER /.V asbestos mixers Taslk VL--Mmmbee of L**f Caw Draft* omd Ret* per 100DCO Monitors ItfrtaW'lfltHCiaM'*C CapiftftMOiBm SMttawW Oerac ywraiijwfttiMimai IMnuflSSMa I.la* stw , frawra m* . Illft Um Cwh Pttlftt * nu ma > t ftkwHMlIMdnftftalc immediately surrounding the asbestos-pn>- suggestne of cancer of the lung and in .dudng areal it practically identical with that cluded such diagnoses as mediastinal o( eight countiei selected lor comparison. lymphosarcoma, mesothelioma, cancer of the While Megxntie County hat a rate nearly teg with metastases' to tong, abscess ot lung, twice that o{ the combined eight selected and cancer of the pancreas. One other was counties, it is lower than the rate /or (he diagnosed on the basis of x-ray only. In Province, and ceniidetably lower than the addition, there are now firing four eases in rate for Montreal. The figure (or Montreal which the diagnostic evidence is strongly would certainty be higher Accept for the suggestive ot lung cancer. This is a total of very low numbers o( deaths reported for 3J case* of all types, including 10 'sus 1950 aod 1951, and it would appear that pected" but unproved cases, and 4 that are in those years tome error in reporting has stiU living. The remaining 19 constitute she Undoubtedly been made. On the basis of the total of proved cases of cancer of the lung other yean, 1950 and 1951 deaths would be among the asbestos miners since 1940. expected to be about 200 greater. This The proved asts avenged 59 years ol would molt in a rate of -40 per 100.000. age at death, and varied between. 57 years The only possible conclusion tram this and 68 years. Their working span covered comparison if that there is no evidence that periods varying Ircrn a minimum of 14 the persona who five and work in the coun yean to a maximum of 57 years. Only ties surrounding and adjacent to the - three men had lest than 25 years of em besMi-ptoductnf sttas hive any greater ployment in the industry. Seven among incidence of lung cancer than those who those on whom such information is avail- live elsewhere in the Province. aUe had a weighted exposure placing them Comment on Alt Retarded Lung Canter in Category III, and six worked in an Cores, Leving end Dead, among the Atbei- exposure represented by Category 1. tos Miners.--Although a simple enumera There were only 17 among these proved tion of all the known or suspected cases of lung cancer eases in which we have in- cancer of the lung in these areas has no lerenation regarding the presence of a- ' particular value fterm a sui'w'teal point at view, it it of intertai to summarize such bestosia. Aabeatost* was present m nine, cases for the record. Then were nine deaths although it was minimal in two. Two path prior to the beginning of (be time period ologists disagreed regarding its presence in covered by the study, including one in which another. At least seven of the 19 proved the diagnosis was mediastinal lymphosar . lung cancers, therefore, were not accom coma. Doting the period covered by this panied by aibtstoaa. inveviczrion, there were nine proved esses and three suspected cues in the cohort Summary and Conclusion* Through 1956 and to date in 1957. there Interest tn tne question of whether there were eight deaths, six of which were merely may be an association between lung cancer {! i : / `/'Is- A. M. A. ARCHIVES OF ISOUSTRIAL HEALTH tnd exposure 10 asbestos has been evident was not possible to trace 111 of these for since the report in 1913 by Lynch and Smith the whole period, but 5171 of the remaining of a case in which lung cancer and asbes- $938 were found to be stilt living in 1933 tosis were both present. As additional cases or later. Of the 187 known dead, cancer in which the two diseases coexisted were of the lung was considered to have been reported, a causal association appears to rosonably proved in 9 and to be strongly have been gradually accepted by many suggested in 3. authors, although some workers considered The members of the cohort were studied the correlation to be tneondutive. The pres* with respect to age, length of employment, ent study was undertaken in an effort to de a weighted average of their exposure, and termine whether a causal relationship did, their smoking habits. It was found that in fact, exist between exposure to asbestos, 4673 were smokers within the definition of _ and oncer of the lung. that term as used in this study. Thirty-four Since most orlier studies had been per cent of the cohort were more than 45 limited to enumerating the hut; cancers years of age. and thirty per cent had been found in certain selected samples, such as employed for longer than 20 years. Thirty oses coming to autopsy or death certificates per cent had a weighted exposure which in which asbestosis was mentioned, it was .placed them in the category ol highest ex apparent that they could not fulfill the re posure. quirements of an epidemiological and sta tistical approach to the problem. The present study was. therefore, designed to meet the requirements of this method. Alter a preliminary survey to explore the availability of reliable information, data were gathered on workers in the asbestos mines in Quebec, based on their medical records. A cohort was defined as a group of asbestos miners having at least five years of exposure and who were in the industry The mortality rate lor lung cancer, as computed on the basis ol nine "proved" deaths among the cohort was 23J per 100. 000. When the three "suspected" cases were added, the "total" rate for the cohort rose to 31.8. The importance ol the suspected but unproved cases in determining, there rates has been reiterated because it is likelr thit such cases would not be included in the statistics for the general population and because they influence the results so mark in 1930. Data relative to their characteristics edly. were collected and their status at the end According to tht findings in this study, of a six-year period of observation was de the mortality rate from lung cancer docs termined. In the case of those who had not appear to increase with length of ex- . died, an exhatsstire search of death certif posare or with degree of exposure, a fan icates and insurance records was carried out which presents strong evidence against the in order to determine as nearly as possible carcinogenicity of asbestos. the exact cause ol death. Mortality rates Comparison of the experience among the from lung cancer for the general popularran asbestos miners with that of various seg of the Province of Quebec and its various ments of the unexposed, comparable popu counties and for the Dominion of Canada, lation siws that the observed number of as well as the United States were calculated deaths among the miners is not significantly from statistics collected in the appropriate greater titan the expected number. The rate - places. Comparisons of the rates obtained for proved cases smong the asbestos miners for asbestos workers and for the other popu (23.3 per 100,000) compares well with the lation groups were made according to ac rate of Z2.S per 100.000 for the rest of the cepted ftatistical methods. Province, 2? 1003)00 for adult Records were obtained on 6091 persons males throughout the Dominion of Canada. who fulfilled the criteria of the cohort. It It also compares satisfactorily with rater 650 tV 17. /'. nst !7 LL'XG lUWM IS ASBESTOS MIXERS of 37.2, 25.3. and 3.0 obtained from various source* for adult males in the United States. Finally, in this matter of comparison, it would appear that the world-wide experience of persons exposed to asbestos dust is not 6. Uclneus. W.: Experimental Albciioirs. Sifmcu. Zisekr. .-illg. Path. I4-J7>.7. 1951. 7. *Oehrenv W, Jr.: The Clinical Picture and Paihohrg* of Aibesteus. 2tiOir. Unialtmed. a Bcrufckniikli. 43:130-140 (June 15) 1931 8. EcrUrogtr. W.; Increase of Lung Cancer worse with respect to lung cancer than that of the unexposed population. The counties surrounding the asbestosproducing areas, in which it is presumed most of the asbestos miners live, have al most identical mortality rates with those of eight counties widely scattered through the and Diseases Due to Dull Inhalation. Med. Klin. 37:1337-1342 (Sent. II) 1931. 9. Bcrtnbhjm, I.: Irritation and Carcinogenesis. Arch. Path. 31033-244 (Oct.) 1944. tO. Boline: Asbestos!*. Deutsche tiled. WchnSchr. 62:928-930 (June 3) 1936- 11 Bohme. A: Rcsulu of Periodical Eiomioatioitt of Workers in an Asbestos Factory. Bcitr. Province, and are lower than those for she remainder oi the Province, and much lower than the rale for Montreal . Since 19-tO there have been 19 cases in which the diagnosis of primary cancer of the lung may be considered to have been proved. Approximately half of these eases SUikosc Forsch. 1104. 1951. 12 Bovici. O.: Asbestos-Milling, 31arkciing and Fabricsiion. Iniomiaiion Circular So. 6869, U. S. Dcpanmcnt of lire Interior. Bureau of Mines. 1935, pp. 1-36. 12 Breslow, L.; Hoaglin, L-: Rasmussen. On and Abrams. H. K.: Occupations and Cgsrcste Smoking as Factors in lung Cancer, Am. J. were associated with asbcscosisr AH but one Fob- Health. (Feb.) 1934. died in the recognized "cancer-age" and at least one-third had only the lightest ex posure i Category li to asbestos dust. On the basis oi what are believed to be complete and reliable data, it seems fair to conclude that the asbeitos miners in the Province oi Quebec do not have a .signif 14. Bristol. L. ,t.: Roentgenologic Aspects of Silicosis end Aibeitom. A. M. A. Arch. Indust. Hcaith 11:159-195 (March) 1955. 13. Cancer oi the Lung: All Evahintion ol the Problem. Proceedings of the Scientific Section. Annual Meeting. American Cancer Society. IncNor. 3-t. 1953. New York. American Cancer Society, Inc. 1936. . icantly higher death rate from lung cancer than do comparable segments of the general population. Furthermore, the death rate from lung cancer in the areas contiguous to the asbes tos operations is comparable to that in areas 14. Carrier. P.: Asbeitosis Cancer of .the lung, in discussion on Smith, W. E.: Survey of Some Current British arid European Studies oi Occupa tional Tensor. Problems. A. M. A. Arch. Induct. Hyg. 5:762-363, 1952. 17. 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An. j. Pash. 18: 123-135 (Jan.) 1942 49. Homburger, F.: The Coincidence of Primary Carcinoma of Lungs and Pulmonary Asbestosis: Analysis of Literature and Report of 2 Cases. An J. Path. 19:797-807 (Sept.) 1943. 50. Hem. D.: la Lung Cancer on the Increase? Evaluation of Present Day Evidence: Cancer of the Lung, Proceedings of the SdmtiSc Section, Annua! Meeting. American Cancer Society, lot. Nor. 3-4, 1955. 51. Hontig, F.: Clinical Considerations on the Question of Industrial Cancer of Asbestos Work ers, Zuchr. Krtbsfortch. 47:281-237, 1938 52 Hutper. W. C: Cancer in la Relation to Occupation and Environment. Bid). Am. Soc Control Cancer 25 i)49 (June) 1942. 52. Hucper. W. C: Significance of Industrial Oncer In the Problem of Cancer. OccspL Med. 2:190-200 (SepL) 1948 1 54. Hucper, W. C: Eovircraneniai and Occupa tion*! Cancer, Public Health Service Supp. 209, U. S. Public Health Service 1949. 58 Hneper. W. C: A Methodology for Environ mental and Occupational Cancer Surveys, Pobtic Health Monograph No. I, P. K. S. Publication No. 12. U S. Pubtic Hcahh Service I9S0l . 58 Harper, W. C: Environmental Lung Cancer. Indus!. Med. 20:49-62 (Feb) 1951. 57. Hucper. W. C: Occupational ud Environ mental Pulmonary Cancers with Special Reference, to r.uwdnp, 7th Saranac Symposium rn Pncixnocotuosts. 1952 58 Hucper. W. C: A Quest Into the Environ mental Causes ol Cancer of the Lung, Pub. 652 Po/. J7, /wr, JPM LUNG CANCER IN ASBESTOS MINERS Health Monofnph N'a H P. R S. Publication Ha 452. U. S. Public Health Service. 1955. 59. Hueper, W. C: EmirwRunul Cuki oI Cauerf of the Long other than Tobacco Smoke. DU. Cheat. 30:141*158 (Aug.) 195a 60. Itscibacfccr, K. J.; Rina. H,, and Hardy, H. L: Asbestosis and Bronchogenic Carcinoma: Report of Ooc Aotoptied Cik and Review of Available Literature, Am. J. Med. 15:721*732 (Nov.) 1953. 61. Kthnaway, L L, aad Kamaway, N. R: A Study of the Incidence of Caaoer of the Lung and Larynx, J* Hyg. 36:236*267 (June) 1936 62. Kennaway, E. L, and Keonawiy. R M.: Studies of Incidence of Cancer of the Loaf and Larynx. BKl j. Cancer 5:153-158 (June) 1951. 63. Eloca. M. Q.*` Atiocinkw of Si&cosii and Carcinoma of the Lung, Ana J, Cancer 15J549 (Jan.) 1939. 64. Lania. A. j.; McConnell, W. J, and Fttad, J. \V.: The Effects of the Inhalation of Asbestos Dust on the Lengs of Asbestos Workers: Pre* luniaary Study, Pub. Health Rep. 50:1*13 (Jan. 4) 1935. . 65. Lana. A. J, editor: Silicons and Asbestos*!. New York and London, Oxford University Press, 193ft. 66. Lew, E. A.: Use of Life lnsoraxc Corn* put)- Records for Cancer Studies, A. 31. A. Arch. Indust. Hyg. 5:198*209 (March) 19SL 67. Loubach. A. J, and Wedlcr, H. W.: Octo* ptiooal Cancer among Asbestos Workers, Arch, path. Anat 307:397-109, 1941. 68. Lynch, K. M, and Smith, W. A.: Pol* nonary Asbestosis: Caranoma of Lang in Asbc*to*Sit>cota, Am. J. Cancer 24:56*61 (May) 1935. 69. Lynch. K. XL. and Smith. W. A.; Pul monary Atbestasit: A Report of Bronchia] Car* anoma and Epithelial Metaplasia, Am. J. Cancer 36267*573 (Attf.) 1939. 70. Lynch. K. M, and Carmoa, W. M.: Asbes* tosis: Analysis of *0 Necropsied Cases, Dis. Chest 14 :S?4-8S9 (Nov.-Dec.) 19*8. 7L MePheeters, S. B.: A Survey of a Croup of Employees Exposed to Asbestos Dust, J. Indust Hyg. 18229*339 (April) 1956. 72. Merewether, L R. A: The Occurrence of Pulmonary Fibrosis and Other Pulmonary Alee* (bos m Asbestos Workers, J. Indust. Hyg. 12: 193 (May); 2J9 (June) I9MX 73. Merewethtr, E. R. A, and Price, C W.-. Report on Eftecu of Asbestos Dust on the Lungs and Dust Suppression ta the Asbestos Industry. London, His Msjesty's Suiionery Office, 1930. 74. Merewether. E. R. A.: A Memorandum on Asbestosis. TuUrdc 15:109; (Dec.) 191); 15: 152 (Jan.) 1934. 75. Merewether, E. R. A.: Annual Reports of 'the Chief Inspector of Factories, London. Hit Majesty's Stationery Office, 1947. 76 3fercwcUr. E. R. A. editor; industrial Metfkme and Hygiene, London, Bulir'wortfc k Co, Ltd, 1956. Vol. 3. . 77. Nordmartn. M.: Tlie Industrial Cancer of Workers in Asbestos. Ztschr. Krcbsferch. 47:28ft* 303. 1938. . 78. Kordmina, XL. and Sorge. A.: Pulmonary Cancer Produced by Asbestos Dust in Experi* mental Amtnals, Ztschr. Krebsfordt 31:168*162. 1941. 79. Phillips. A. J.: Mortality fron Cancer of the Lung in Canada f 1931*1952), Canad. 31. A. j. 71242*244 (Sept) 1954. SOL Stupe, E.: Further Consribuucas to the Roemtenotefical Diagnosis of Asbestosis. Ardi. Gcwrrbcpath. . Gewerbehyg. 9291*406. I9J9. 81. Smith, K. W.: Pulmonary Disability in Albertos Workers. A. M. A. Arch. Indust. Health 12:198*203 (Aug.) 1955. 61 Smith. L W.: Pneumoconiosis ami Ltotg Cancer with Special Reference to Silicosis ami Asbestosis. Cornpens. Med 32*10 (Nov.) 1949. 83. Smith. W. L: Survey of Some Current British and European Studies of Occupational Tumor Problems: part HI. Asbestos. A. XL A. Arch. Indust. Hyg. 5242*36) (March) 1951 ft*. Stoll, R.; Bass, R, and Ancrist. A.: Asbestosis Associated with Bronchogenic Car* onoma. A. XL A. Arch, let Med. 88:831*834 (Dec) 195L 85. Tricky, L.: Occupational Lung Cancer, Acta Union internal. centre Cancer 3253*373, 1938; alsa ZcranlbL Ccwtrbebyg. 2723. 1910. 86. Vorwald, A. J.; Durban. T. XL, and Pratt. P. C: Experimental Studies of Asbestosis. A. XL A. Arch. Indust Hyg. 3:1-43 (Jan-) 1951. 83. Wcdkr. H. W.: Asbestosis and Lung Cancer. Deutsche med Wchnschr. 69:575*576 (Aug. 6) 1941 88. Wegclhn. C: Changes in the Lungs in 136 Cases of Asbestosis Observed in Finland. Acta radiol. 38:139*152, 1947. . 89. \\crbcT, XL: Pulmonary Asbestosis Asso ciated with Carcinoma. ZcraralbL Arbritstaed u Arbeitsschutx 2:179*180 (Nov.) 1951 90. Wood W. B, and Clojee. S. R.: Pulmonary Asbestosis Complicated by Pulmonary Tubercu losis. Lancet 2:954-956 (Ocl 31) 1921. 91. Wyert, H.: Asbestosis, Postgrad. Mod. 25: 631*638 (Dcc> 1949. 91 Wjmdcr, E. L, and Graham, A,: Etkftwgic Facmrs in Brcndiiogeuic Carrinrraa m otweta* Mctercnce tn tudutrial Exposures; Report of 857 Proved Cases, A. XL A. Arch. Indus*. Hyg. 4 221-235 (Sept) 19SL 8row--7~rsq*i hiWft W W OmM |MI / 553 ^O 7'*^ * A.P7C2ST PttTXg. Ltnacs, kat7 . USDSATCHI XCZSSSZCn SO. 10-;?-25 E3-I552: October 27, 1?5? arsurd 12 coon . AD7CPST i Perfcrrsod on the use day t 7 ?.X. is Kar.rills, J{. J. ??X~~.1: K.=hel Jarla, X. 3. lfi/b j/ /- /srz /?* &***-}, if//, '' 2 =w. *ST, i/ 9 f MS? l/.t .w; i .iM /.x i ^ 'Jl .tV oo relinhlc vri, jjilticijeitc i-irein. An Epidemiological Study of Lung Cancer in Asbestos Miners i^. 'VVyt- *yy P gtnou'n. relatively /tnicture hi a eh,-: 'jdcut to ilimiuidi ictiuu. DANIIL C MAUN. M.0,, .A T. OAVIO TtUAN, M.A,, HntbvrgH <y KSL If aslwstos is ir. carcinogen, the insome property w' Ever since Ihc pronounced increase in whose work is also fra|ucut(y referred tn joincthing more the ixxcUlence f Ixxixg cancer among males ;xs establishing a connection betxveen asbvy- These authors became ap|arcut. there have liccii attcni|its to associate it with one <ir another of the. tosis anil cancer of llie lung, reput-ted in 1951 that cancer of the lung was present 1t until some more direct carcinogene. various dements in the environment of in of asliestosis cases examined bv r composition prudu- man. The approach used hv sranc workers has 'been t suspect one or several sub stances ami then set aliout ill an intensive search for lung cancer among jersons who have hatl auj* exposure to llue materials, du this connection. Smith c writes: "The tendency of authors reporting- the coinci dental occurrence of primary lung cancer with silicosis or with any other theoretical him. in Wl. Nonlmami and Surge*' claimed to have pruducal lung cancer in mice which they eX|iscil 111 aslicslos llxi-l. Since 1951. additional cases of cancer of the Ixuig. coexisting with aslx-sliisis have been rv|Mirled. and. accnrillilg to Kueprr4* about 100 such eases had been reported up to 1955. As a result, an association between the two diseases appears to have been it- ijsbestos niight lxJcinogcn" which on .vlopmcnt of a \ brought about by-- ;:hc asltcsins, such Thus the Uxeralu sl port the thesis lhI way rel.ated to h ji ca_n_c_e_r, is rb..y. no ii etiologic conditions, has been tn emphasize cepted by many ;uUhors._antl several writers I gethcr, it is perh. the percentage relationship in extremely were using the term `"asbestosis cancer" enlightening. A small scries of cases, with contrul cases the lung. WerlH.T.'** in 1952. stated cate |the majority of tfv- which are not in any way comparable." gorically that in l(-t to 17*r of cases of I nut epidemiologies ft xvoulil seem ineeitaMe that nslk'stos asliestosis. after a laleiit |>eriil of about ineiits necessary should come iimler scrutiny in this manner, I /) to 2(1 visit's. eari'iiiiMtci Iuvumivk <-Mab- ^jidi-midiiL-'ilil lw because prnfoiigcif eX|Nisurc to this material fisfied in the lung. sod most of the au is known to cause a specific type of pneu moconiosis, ami because persons who show this form of pneumoconiosis rsfleil contc to On the other hand, not ail authors ac cepted this alleged association without reservation. Saui*e50 in 1939 reported that to having done so. that SUCiTetling am sions and-general!: autopsy and provide a ready source of material fur study. It was iix this way tlxal reports of the simultaneous occurrence of lung cancer and asbestoses began to accu mulate after the report of a case by Lynch and Smith** in 1935. Within the next 10 years, about IS aihlmonal cases xverc re portal, and in 1954 Mcrexvethcr ** revicxved all deaths from aslx-stosis recorded in Eng land since March. 1924. I zing cancer oc curred in 16/o of these cases. Gloync.'" Accepted for imliticnliiui Jan. 2IJ. t9$8. Ttiis uudy' was made possible through a grain fmnx the Quebec Aslesios Mining Aisnrialirm. Medical Director |Dr. Itraini) -amt Slaiistical CimutltMit (Mr. Troaol. Inilttscrial llvuivnv Kmusblioo. lie had discoiered no eases of lung cancer I the works which lF milling U20 rases ul asbcslusis which he t example, have we had examined; and in 1942. Holleb and population of asfc Angrist4* expressed the opinion that the several authors w; mtmbcr oi cases of asbestosis with lung jerred incidence oi cancer was tun small for statistical evalua of persons who al tion. In 1947, Wcgelius** reported 126 . that this incidence : radiological!}- diagnosed cases of asbestosis Lrs. generally. \\ among 476 workers in Finland, ami found unable to find an on cases of lung cancer in this group. calculated the inc Cioldblatt and (.loldblau in their section al jniong a (lopulatio Mereivcther's latest Ixink,4* State: "But at asbestosis. and no; no stage in all these impressive researches jutopsv. With ttu- iwas any eluc olitained which might have offered any support to tile possibility that :isl>esXos cntiVl act as a rari'iimgrn. There by Ijnlf.5' i.ue oi data on er-P.-urc : ami even TMl lull's -. ftrmin--Trwir. 6J4 9S8 \ -i . 'SC VAXCI-R IX ASHI-STOS MIXhKS r', no reliable critcriun by which owe out -'3 nticilte carcinogenicity ami, a* is well . gown, relatively minute changes in the : '! iwcture of a chemical carcinogen are sulfiient to diminish tir eliminate carcinogenic j ition. "t If asbestns is indeed to lie regarded as a ucinogcn, the neeil is felt to demonstrate jute projicrty which can be regarded as ferred in \ oroething more than inertness." asbesorted iu * Present rimed by Sorge ancer in *tOS dtlxi. These authors advance the theory that, il some more cx(>crimcti(al evidence ui. carcinogenesis, by asbestos or a de position product of it enn be obtained, ;tos might lie considered as a "eo-car- n" which only ittduccs a further dclopment of a prcnenfilastie condition anew of ight about by something independent of sis have asbestos, such as an endogenous factor. 'ilttper** Thus (he literature, while tending tn *up- *rtcd up irt the thesis that asliestosis is in some * between ,y related, to the development of lung been se icer, is by no means unanimous. Alto- rf writer* ;her, it is perhaps more confusing than nicer" of lightening. A careful review shows that ted Qte- jke majority of the re|*orts are ermical and eases of jot epidemiological. They lack nvmy cle of about fs necessary for the application of es tetab- r Qtors ac- without rted that 'g cancer vhich llt neb and that the "fob lung I evalua ted I#, lidcmiolugical leehuiitues to their content, most of the authors do not make claim having done so. What has happened is succeeding authors have drawn condu- and generalised beyond the of works which they quote. Xuwhero. for mple, have wc fouml references to a fulation of asbestos workers, although eral authors who have quoted the ob- red incidence of lung cancer in autopsies if persons who also had asbestosis imply this incidence applies to asbestos work- abestosi* td found * group, -"ction of "But a, -Searches ?bt have Hity thm ' There generally. We have likewise been ile to find any study which actually [culated the incidence of lung cancer g a population of persons who had ibestosis, and not just those who came to ttftopsy. With the exception of a (taper iy Doll,** none of those reviewed gave any on exposure and dust concentrations, even Dull's pajicr merely tuetdions kroon--Train "scheduled" areas, hy which is meant, "those areas where processes arc carried on which were schetluled under the Asbestos Industry Regulations of 1931 as being dusty.' Tlterc is, furthemuire, a complete kick of dcliitiliuii of terms as used in the pub lished literature. t''or example, the lenu "asbestosis," as used, may refer to changes observable only by microscopic examination of (fie fung- (issue, or if may mean a raifioIngirotly detectable condition. Most of the published re|K>rts obviously included women among their cases, but some of them do not give the number or projHJrtioii of women involved in the study. There is also a lack of uniformity as to what type of exposure most studies have dealt with. Of 99 roses enumerated by 1 (neper " in 1955, only II) api>ear to have originated in the United States, and 7 in Canada. Some of the earlier reports ap parently included asbestos miners, but it can be assumed, since 82 of the 99 cases had originated in England, artlT since no asbestos mining operations arc carried on in that country, that ninst of the reported cases have involved workers in the textile or fabricating industries. Such factors as smoking habits, family history of cancer, length of time in the industry, and age of the individual case arealso notably absent in the majority of these reports. With this understanding of the limita tions of the existing literature with respect to epidemiological generalization, it may be of value to consider in somewhat more de tail some representative earlier publications, a few of which were referred to briefly above. One of the most detailed studies anil one which deserves the most serums considera tion is that reported by DollM in 1955. This study reviews causes of death among asbestos workers IxiSvd on coroners' rec ords. It also attciiipls to estimate the risk by studying records of uicn who worked fur at least 2d years in exposed situations. 635 1 I f it. .1. .tmtttrts at txt'i sTKi.it. ni:.n.Tii if.f*.v<; c.t. ' . Drill concluded licit lung earner was .1 >|kcilic" industrial lia/nrd of certain usln-slo> worker* ami that. after 2t) year* ofcx|in IllUe cancvr io oilier fn* "I ("tiumociinus. Ijeath cert: >i> wa t.7'<. anl in 1IW cases which ijuve beet: prowl mu to liavc any lyj*e of pitcuniu- lit enhance sure. the risk is 10 times as jcrenl as for coniosis it was 8.3%. Gloyne considered I shat the ie the general imputation. This artirle is int|>ori;mi for several rea sons, in addition In the definite eoiielusious at which it arrives. I'Vir example, it lcgius by stating tied "in view of ihe infrei|ucuey of asbestosis. this large nunilier of eases (61 cases of lung cancer 1 su,exists--but "tlie mortality of the asbestos workers" u, Ik- "disturbing." lurst of all, it is obvioux lliat the |*apvr lines not deal with die "morlality of asfieslos workers," and seeonrflr. it must be Imriio in mind that all of [), t iloyne's eases were submitted to him for study Invause the findings were unusual ,gcs of th< The dang fate found :he gener: jge. occup iiich as Sr. i I .yuch.*" does not prove- -dm lung cancer is an oceu]iatioiial hazanl of asbestos workers." for uncomplicated pneumoconiosis. * It can jthc first e: reasonably be assumed that cases, including {(arcinoma Neither this article nor miv previous ime those of asbestosis. In which the finding, lutopsics 0 which We have examined pr.esenis any fig- were no! considered umisu.il were not sent ('acroring | urvs to prove (hat asfiestosis is an infre to Ur. (iloyne for examination. As a mat 'demonstra quent occurrence. Kstinntes of the numlwr li-r of fact, in the Kune jmrngraph in Whirl: .zings." T: of persons |<o:eniially excised to asbestos he expresses concent over the incidence Identical w dust in tfie fnited Slates alone vary from rale in asliestnsis. Dr. tdoyne himself Kimsclf. |- points out that the rate for lung cancer iinckleuce . K),<XK) to 35.UIO, and the iueidenee of ns- bestosis of any degree might lie higher than ' based on necropsies at the f^indnn Chest 'snail for > I fospilal was 2l-3'/'<- while the figures of (calculation.' IJofi imagines. - .the Kegistrar-General shoiveil only 2.4%. have used : This study, like so many uthers, involves He thus recognized that autopsies on a cer jtor an tis-r autopsy reconls. The number of |x-reons tain selected group of cases were not rep. - with ashes: involvetl in the statistical analysis is only resvutalive of the general imputation. h Klotz" 10 113, representing only 1,1)42.25 man-years woukl scent, then, that notwithstanding thv .uses of lu of life. It is also true tlvit in selecting men value of Dr. tilnym-'s work, its im)irtanre dimes as 1: wlu had Wen employed for at least 20 as an index if the prevalence 01 lung can- .jshestnsix. years, tin- study automatically excluded eer in asliestoiies has lieeu misinterpreted iltose who died (mm other causes after - by some who have quoted hint. All that it shorter employment. really shows is the fact that in a. group of | Behrens. ;mated that. Ifilcralnre. - Another reason why this publication is 121 eases, selected (or special study pp. ithc_ lung--t of iiiiiiurtauce is a statement which it con manly liecauSe they seenieil abnormal bv ithis is an tains to. the ctfect that `-'the strongest evi preliminary exaniinatiiHi. 17. nr 14.1%, haii incidence o dence that it (lung cunvr) may la- a hazard (uug cancer. rhich were (in asbestos workers) has la-en produced Mcrcwelher75 in 1947. in the report of cause some by Mercwethcr and by Gloynv." the Chief lns(n-ctor of I-actwries, reviewed possibly- hi In 1951 Gluyne<l presented a review all cases reported between 1924 and 1946 lases were of 1205 autopsies on persons who had in which asliestosis was the cause of death iplies to the worked tn various dusty oceuilions. This or a ctiexisting condition. This work was jjppears to number inefudert 132 asbestos workers, of filler rMeoded lit include nil sueli cases re- jutopsics on whom 121 showed "piK-uionenniosis"--prestimahly asbestosis. Primary cancer of tinlung occurred 17 times in this group, an incidence Rite of 14.1*. for lung cancer among asbestosis cases coming to autopsy. There were in his series 796 cases with sili cosis, anil <>.9fr of these also showed pri mary cancer of the lung. The incidence of |nirtiil up to IKwinlier, l'*54, by which time Jarhich 6 casi there were 344 detilhs, including 205 malts itonnation f: and 139 females. Among them were 5J aot justify cases 1.16%) of cancer of the lung, 41 in (mortality rat nudes ami 14 in females, ft is i(uite possible Perhaps 1 tied a large hiioiIkt of n.U-s(ittiis who tin] (.ively on 11 not die of Ihcir asluslosis, or in whose (in' 1955 ho I'l'l. tr. June. I9`* ]ntun--TriM 636 1 rf'RlAL HEALTH "i'.VG EASIER IS ASHI-STOS MISERS of pneumocoilin- jlcoth certificate it wa* imt mcntiimvd, .may prior tu (Iwi .tale amt enumerated a total 169 eases which lave been missed. The import of this 16% of 99. Eleven of these were those dis type of pneumo- it enhanced by the simultaneous statement cussed by Don ** and may Itavc been cases loyne considered pat the incidence of lung cancer in aulop- stos workers" tv of tlie general |Kipula(inti is only l*i>. all, it is obvious-^he danger of attempting to eiitiqiarc a d with the "mor- (ate found iu 344 cases with the rate fur and secondly, jte general imputation without respect to cnvernl by other authors. Light were diseovvred by Keimaway ami Kcnnaway * in an analysis of death certificates, and, unless Mcrewethcr's study was incomplete, these cases should have been'included in his re that all of. Dr. ae. occupation, and many other variables, itted to him for ch as smoking habits, is obvious, rs were unusual 1 Lynch," who with Smith * hail reported coniosis. It can fte first case in 1935, reported 4 cases of . cases, including lucinama of the lung in a scries of 49 port. Of the remaining 80, it is quite i*ssible that the 31 contributed by Mcrcwcther and the 17 by Glovitc contain sonic duplication with each other or with those of other English authors. .. Itch the findings -Jutopstes on workers in an asbestos manu al were not sent fcturing plant who were shown to have dion. As a mat demonstrable deposits of asbestos in the Principles of the Epidemiological Method 'agraph in which ''mgs." This, of course, is mt necessarily Dorn" has pointed out that much of what r the Incidence Afentical with the disease asbestosis. Lynch, Gloyne himself jjmsdf, points out that, although this is an for lung cancer fsidence of 8.2%. "laith arc ton > London Chest Vnall for very serious statistical iv|ics of the figures of Llcutation." Nevertheless, later writers .ved only 2.4%. iye used this paper to strengthen the case topsies on a ccr- pr an association of carcinoma of the lung is now thought to lie |>crtincut concerning the comparative frequency of lung cancer in different imputation gniuji* has been devcltqicd frum (lie analysis of dinient ma terial, particularly surgical and autopsy records, supplemented to some extent by the reported impressions-of various clini s were not rep- Ifth asbestosis. It is also of interest that ' population. Ii \k>u ** found only the same numbin' of withstanding the lues of lung cancer in a series nearly 10 its.importauce imes as targe, i. e.. 4 in 478 cases of icc of lung can- Lbestosis. i misinterpreted 1 Behrens, as died by Merewether,,< esti him. All that it mated that, of 309 cases of asbestosis in the t in a group of ^mature, 44 showed- associated cancer of -cial study pri- lung--giving an Inddence of 14.2%. d abnormal by Yhis is an illustration of generalizing an , or 14.1%, hail Sridcnce obtained itt a group of cases cians based upon their personal observa tions.. More recently, however, attention has turned to the systematic investiga tion of this problem by the same methods that have proved so successful previously in the study of communicable diseases, that is to say, by epidemiological methods. . In order to apply ibis method of investi gation to the problem under discussion, we were of the opinion that a study should be planned so as to provide (1) a well-defined ; hich were undoubtedly reported only ben the report of use some of them showed lung cancer, to tones, reviewed disibly hundreds of asbestotics .whose 1924 and 1946 lies were never rqiorted. The same ap- cause of death -sfits to the conclusion of Tdeky,** who This work was Wars to have reviewed rqmrts of 39 1 such cases re Uopsics on persons with astasia*!* among V, by which time ; ihich 6 cases of lung cancer occurred. In.ding 205 males jrmation front' sources such as these does them were 55 ot justify generalizations with regard to the lung, 41 in artality rates. population group; (2) available data for all members of this population, including the healthy as welt as the ill; (3) a sample which is truly representative of the imputa tion; (4) reliable ami valid observations relating to the problem of the study. . A serious defect, common to most of the studies which have been reported, is that little or no information concerning the healthy people in the group seems to have bc^n available to the author. In order to is quite possible Perhaps no one has written so exteu- draw a generalization regarding all aslieslns stoticx who did ively on the subject as has llnejicr.45" workers, it Is necessary for a study to in | . or iu whose 1955 he reviewed the cases** reported clude living persons as well as the dead. ' 'of. IT, June, I9J,1 us*--Tnun 637 ...... . /f ftw;.;- ; . I> /if' ' VI; ;* rI l $ ??'- * t - :4` * 4 % ;! `<ii>' .1. .v. ./. AKCIIIII-S or INDUSTHIAI. HliAl.ru /.r.vt; r.-i.wi-.H. I.imiting the investigation to cases ohiiiiib Ik* found in another group of llic same site, discussions with - to autopsy, as has bcvii frequently dune iu but representative of the general population. of the asbestos earlier studies, still further restricts its use .It is true that investigation of cases from with clinicians, p in generalization. The problem with which such a sample can furnish information ol City ami l*r<. we are mtieerncd is whether asU-stus valuable for research, hut the use of (|,j, and of the v'.ui.. miners experience more lung, cancer than information in drawing generalizations i* other interested j docs the general imputation. Tlie answer necessarily restricted. It is the obligation morbidity data, ai necessitates the collection of reliable infor of both the investigator and of those who were available fr mation on aslicstns miners as a group, as read his report to make prti|icr comparisons hospitals in Mom well as on the general imputation. and to draw only those conclusions which the 13 cancer dele It seems advisable to discuss the tlilTer- arc valid and justified. A good statistical incc. However, b ences between the epidemiological approach study of cases of cancer of the lung occur- * tality in lung ca: and that used in the studies which have ring in a group of auto|>sie$ can lead to a to depend upon been reported to (bite. A wry important proper inference nuircniing the frrqucucy consideration is the fact dial lung cancer, uf lung cancer aiming eases euniing tu These we found vital statistics dc^ in spite of its increasing numbers, is still a autopsy, but only to such cases. For in of Ilenltli_jn_i>uc: disease of low incidence: that is, in a given formation from such a study to be pro. imputation not many persons will eoutraet jccied to some larger group, it is ncces.urv limiuary survey, it five and dvtailo this particular disease. This fact requires that the autopsies represent a goad saiitpjj. iatlwred with reV that large samples or groups must Ik* stud of that birger group. To assume that such employed iu the : ied tu provide mennlngful results. ls: the case lit any particular series is dan ami the mortality Recognizing the difficulty of obtaining gerous and likely to be false. population. such large samples, most earlier writers There is some danger that the figures Following this deviated from the epidemiological method rc]K>rtcd by some authors may be miscuu. initial effort was i and sought to cireutuvetit the requirement st rued as a|i|>tyiHg to aslicstos workers ur if data relating i of observing well |ktsous by (1) cunqiar- even asIxTSlos miners, when; in fact, tlK. been processed tit: ing the relative frequency of cancer in vari authors in question do not make this gen ford Mines since i ous -sites: C2) coni|M ring the rebliee realization, nor can the generalization |,,. fimilar infnrmnlii.: frvqueney of cancer iu a group of hospital made fur llie reasons stated. Close study of jt A.-Ik-sIos, One. ized patients: f3> comparing* Ihe relative the reports reveals that the percentage* records included I. frequency of cancer in a group of cases cited relate unlv to the group ot autopsies sonal medical hi: coming to autopsy. coveretl by the | Articular investigation. ntunlK'r of years i. Attempting to compare tu-o imputation groups, lnobing only :!i Ihe rebitive fre quency of cancer in various Isiily sites, The present study, in contrast to the earlier works, has been planned to utilize the epidemiological method. A well-defined .if weighted expo* the individual's he: ,if his death. may result ill finding a higher |<cmutagc group of asbestos miners lias licen estab- . From this infor ' (relative frequency) in otic of the groups, lished in such a way that it constitutes a to fonttubite a "eoh when, in fact, the mortality rate of cauccr good sample of the whole population of defined, should be of a particular organ is exactly the same asbestos miners in QucIkv. Data for all whole group, arid c in both groups. This is very clearly dem members of this group have been collected definite |ieriod ot ti: onstrated in the excellent article by bom.1" and analyzed. Those concerning lung can experience indicates The mortality rite front a lenticular cause Is the true measure of comparisoii. ft is apiKtrent that selected groups such as hospitalized patients or autopsy cases may tint be iu any way representative of cer have n-ceived most careful considera tion. I Mails of the methods employed will Ik*, set forth biter, but the tyjie of approach is ctmsitleretl to |>vmut of fair coiniiarisons and valid gvucmlirjit'nms. of aslK*slnsis in U-spostirc must Ik* s<> ingle, the cohort w: every miner who h. live or more years, a larger group, and lltnC iu dealing with < Collection and Analysts of Data employment rolls in such santpivs. the observer may easily find A preliminary survey of (mtcntinl sourevs' nones |mscd personn more cases of a given dise:tsc than would of information in I'elirteary, 1956, involved of employment. we MH I'ol. 17. Junr. /(ip Jninn--Truan r~ ?r ' rv i._."*.i!|ufi, yW'/J" JW 1 HEALTH Ii\y<; i as am in ashus TON MIXHKS ajrie liar oscussiuns with the physicians in clv.rgc ipulation' * *^e as^os,os sompanics' programs ami ;es ith clinicians, pathologists, representatives ormation ^ awl Provincial health drinrtinents ` of this f '*" ^n,la<liau Cancer Society, ami ttions ` 't)icr interested persons. It was (uuiul dial bl'gation ^a,a' although switvwliat limited. OSC who V parisons fmto such Sources as the '* Montreal anil Quebec City, ami S which * ^ caKCer detection centers in the I'rovtatisticnl ***' ^owcvor> because of the high nitir- _ 0<x^r ility hi lung cancer, it seeineil advisable ' .`.j depend upon data relating to deaths. a ehrse we foumt to he obtainable at the equency ;L j dcjiartim.'JJt of the Mwii.vlrv For ' v# tlealth ui Quebec City, From the pre^ `Taiinary survey, it was np|>arviir that extcii- (v detailed in formation could be sajn Y Vlhered with respect to both the (ktsoiis . , 'aploYcd in the asbestos minuet itulustt-v .. jb! the mortality figures for the general *""7 ^`Ulatiotu figures d following this exploratory survey, the tniscon--u^ort was directerl to the collection hot* or .p data relating to all workers who had wt the "VTM llr0ccs-'ic'f through the clinic at Thet is gen- ),rtl ^fio0* since its inception in 19-47, and ion *bc ta,ilir information regarding .-.II workers udyot'V Asliestos, Que. Data fnun the clinical entag-es- rds included Vhe age, family and \>er- topsies l' medical histories, snvoicing habits, on. mber of years of cx(>osure, an estimate to the' weighted tspwutc, and the course of utiliae .in.d.ivid.ual's health status or the cause defined ? '"s . estab- a From this information it was (mssiblc utes a 9 formulate a "cohort" which could be well ion of `Jfitusti. should be rqircscntative of the for all rjtolc gruP. and could be followed for a fleeted ` kfiot* period of time. AH of live available g can- Itpcrirncc indicates that the developnient idera- a aslicstosis in less than five year., of ex it will jwure must be snmewhat rare. Accord>roach Jgly. the cohort was defined as including risons }\try miner who had a total cat>osurc of or more years, and who was on the u iploymcnt rolls in 1950. Office and utlicr icxposcd persnnnel, vgar.llcss .f Iciigih 'toutrvcecds j1 vu'i,h,y'"1"'- "-crc nut included. This cohort was iliett followed by means of the annual physical examinatioti records thnmgh a six-year interval, 1951) through 1955. All data regarding litis group wi-rv then tabulated in urtler In delenuinc the characteristics uf the cohort. I'nr. those who survived the entire period, reference was made tlie phy.-iral examination resiill.s and x-ray findings at the end of the ]>criuil. Those tvhn had died were tabulated sepa- ratclv. and the cause of death was eorruborated by cxamitiaiiun of the death certificates.' A further search was made concerning those ill the original cohort who remained ineu'cnunleil for when Ihc living and the known dead had been tabulated. They represent men who had left employ ment through retirement or resignation. Kvviitually, all hut a small tuniilter of these were nccouuicd for as either living or tlead, :uul in the latter event, (lie cause of death was substantiated in a similar manner, and the results added to the original list of deaths. __ Death certificates' lor the Province ol Quebec for the years 1952 to 1955, inclu sive. were reviewed in the department of vital statistics of the Provincial Health Ministry, together with statistical sum maries of the causes of deaths in the Prov ince by counties. All cases in which death was certified as having been due to pri mary cancer of the lung were examined for such information as (dace of residence. uccn]ialiun, dale of death, hospital in which death occurred, and whether or not an autopsy was performed. Cases in which lung cancer was given as a cause of death, but in which it was not s|>ccificd as to whether the cancer originated in the fung, were also reviewed in an effort to include all instances of primary carcinoma of the lung in the study. The statistics for the Province of Quebec relate to population, total deaths from' all causes, total deaths from cancer of all types, and deaths 'from lung cancer. These were collected and tabulated by counties and by sex for the years 1950 to 1955, inclusive. .. inw/i--Tnuu i.W . tU'i i- i [ i t i H: i! I * i: ! r * i b t f \ \ i . jr U $ i *V i ji ir 11 i(.-u t- .1. it. A. AHlIIIFF.S OF IS'DUSTHI.It. IIHAl.Tli t.U.XG CA.X l;nnii them, death rales for the general In aildiliou In this .-dialysis of deaths oc Taiuk l.--.X 'rf population of Quebec ami of individual curring in tin: cohort and during the years counties were calculated for specific years under observation, evert' known death from Alt and analyzed by cause. ' cancer of the lung, as well as every case ............ Practically all employees of one enm|iany diagnosed but si ill living, has bvctl t.'iblil.Uo! 1 o-w........... ......................... are covered by a group iolioy of life iusur-. and analyzed. They will lie discussed separ UIH'nk.c.K...i.v..a..................... mice which, fortunately, uvarly all of them ately. from those included in Ihe population continue to carry when they retire. A very and lime-'mtcrval under study. Average few are not covered by this policy, and A comparison of lung cancer tnnnalitr ijtt* |haaQ-r those who leave the industry for one reason ' in the asbestos-producing counties has been or another except retirement usually arc made with that in counties which arc far areas. For . no longer covered, but this is likewise a removed front the asbestos mines anil in I assumption ! small number. As an additional cheek upon which', presumably, no asbestos miners live. ship betweer the information obtained from the clinical 1/records on this group, the records of the life insurance comjiany were examined for Finally, in order to lirmden thu compari son <d death rales in different - population groujis. the rates have been collected for that Categn. Category' HgoryJ._ all death claims paid under the policy, and Canada generally, and for the'United Slate*, 1 particular notice wns token of the claims acconling to the most recent published and Taw.k J.--,V in which the proof of. death was basest on unpunished material. . . lcancer of the lung. ' ' IX'nths from lung rniicer among aslK'Stos miners were thus determined from the clinical records in the medical service of the industry and checked by means of the death certificates and insurance company records. The deaths were then verified individually by reviewing them with the physicians in _ charge of the medical services, lu tins man ner, there was established a |i>| of cases in which primary cancer of the lung is con sidered to have been proved as the cause of death. A fpw cases in' which lung cancer is strongly suspected hut not proved as the muse of death were considered separately. Mortality rates have l>cen calculated using Imlli the "proved" ami tile total of ''proved" Results and Interpretation The cohort which was constructed accord ing to the criteria described in the preceding section has been considered individually and compared with --the general imputation. Descriirtion of the cohort will be presented here a* a preface to the results of the study; (IrieilMl lolmtl | |Vtdi IVikhlvl Vtnal K'+mt Living in 195] (wurkinc ivad 1* H5J fftlml) rw of fucitf OonciotnUr caitrrf uf luttu IHWt nwr rriotint raUMm Snx^rft N`mimu4#ii 1'nUiMa . <0qj uj MX lu | j |$| | 4jai *1^c jo Ktpicnif* Caitiory I..................... II....................... UIInIk...n..o...v..n.. .....^................ YuU__ * Mis ihan OJ*" The imiri; similarly tal< 4. Thi* was tion was aval regarded as besides the < influence the As used in smoker refer anti "susjiectcd" eases during the years un Tables 1. 2. 3, and 4 present age, number der observation. Ctmt|tarisous were then of years of employment, weighted average T made between the death rates front the same ex|msurv. and smoking habits of the cohort. cause among sjiceific segments of unox(iosed Acnoipnrisun of the exposure to asU-stos persons. AH lung cancer deaths. Imth tlust is presented in Table 3. All mcmlieri *tts|HVteil anil proved, were carefully ana lyzed to determine |issiMe rclatiousliip or correlations between (he tlcvelopmeot of lung cancer anti any factor known from the clinical records, such ns family history of cancer, personal history of heavy smoking, of llir ciihiirt were placed in one of thrW categories, representing increasing degrees of exposure Uascd on a weighteil average of tltc. years s\>cut at various levels o( diisiine>s. The degree of dustiness for each job category was determined after consult^, Yrttf IUSO...... W...... |#tt...... iaw...... t8H...... Wf*...... TirfuM....... **|*nvrr* n*r |<rr ' coexistence of aslicMosis. or exposure to tion with (hTmiiis familiar with the coviron- asliestos. '' imiu amt eomtitiuns in the various work Tuiar'rdr |wr !* 640 / */. if, /uni\ to# flrtnm--Trunn i : *v i IAL HEALTH jwNC CANCER IN ASBESTOS MINERS of death* oc- "> --Number cud Pereentage Distribution T.\ki>. 2,--Nwuf'er mi Percentage Distribution by ring the years * ** Agt Length of Employment vn death from sc* Number P*r Coni as every case 9+*...... .............................. i been tabulated ...... scussed separ- ' reknewo............................. cu M 19 1f0t the population J Tout*....................... /. i lftnc* Ac*--....................... WO icer mortality J'Uutiuaejft. Lrnrth or F-mplaymeni ft-9.... MM2... <0 40... TvltU...*........ .......... A fcatl erf I.TQ3 xsm on 03 las OS AMI IS l**r (Voi <o IS 10 3 t nties has been . vhich are far >lrtas- For the puqmscs of calculation, the (nines and in Jt**un,P,*on has been nude that the relation 's miners live. J^'P between these categories is linear, and i the compari-1**1 CateQry 11 '* lwice M dus`y. ually smoking more than five cigarettes per day. Persons who smoke pipes or cigars exclusively were not considered to be smok ers for the purpose-of this study. -nt population 111 lhnx liniC8 a* dusly 2S Ca,e- Table 5 presents the year-by-year ex ctotlected for "r I- perience of the cohort and indicates the CJnitt-d States, i- Published anu 'Tail* X---Number and Percentage Distribution " i by Exposure Category Tabu 4.--Number and Percentage Distribution by Smoking Habits yupMun station 1.1- _-_--_---------- ...._______ _____ meted accord- ------ :------------------------- th* e preceding r` i-*iividualty and. J^irax* EtperanV. Number vai ft MM to tot Cnl u so JO 1 population, be presented * Lea than04ft. t of the study: The fourth variable, smoking habits, was Pmokluf Until* ...... ............... Ncmaoktn . unknown^,.......... Toull___ ........ ................ Nuiahor 4,4(71 ,_MM * lot lion a.s%. Pit Coni T9 SI too inimlier of ileatlis each year from s|>eeilieil ^similarly tabulated and is shown in Table w Mil 34. This was included because the informa Kmi tion was available and because smoking was 1ST regarded as one of the variables which, lilbesides the environment, epuki conceivably lt* Iinfluence the development of lung cancer. causes. In general, a ease was considered to be "proved" as one of primary cancer of the lung when the records showed that the diagnosis had been sup|>ortcd by an autopsy or surgical resection of the lung With microscopic examination of the re **U jAs used in this presentation, the term U4J 20 smoker refers to a cigarette smoker, habit- moved tissue. In one case so considered, however, diagnosis was confirmed by bron- t age, number ;hted average of the cohort, Table 5.--Year-by- 1'cor Experience of Cohort and Death Ralrs per lOOfiOO Man-Year* of Risk re to asbestos All members one of three tsing degrees na an.. ihted average^ as.. AS- us levels o(4 sm.. su. No. AUnAt IWritutim cl vear J.0M J.WJ SA& J.W4 9MS PlOVod Prtnaty Ccovf Luac I S 0 \ 9 Cum si Dtniti SuYffidpft rrtouwjr Ca.uf Luttc Otl*r riM t IS 0 IT W )i SJ 3A Unknown I I ness for each Total*. ..........................*....... . 9 fter consulla- -fiwwl** m(0 |vr WQ.fBu nwo-pun vl rUk* 9 9 I lS SSJDA j i the envlronTotal** rote per ICOAJO man-ycat* uf i various work -- M4 \ . 17, June, Ibitt /frown--Truan 641 rr i: .1. it. .1. .iRCUtl 7-.V <)!' IXIIUSTRI.-U. lllwtl.TU i.cxc c.iwr.K /.v Tabu: tt,--Troivif Cum of 1`riutary Cuneer of the Ijtmg CwN'o. 1 3 3 4 t -7 Oft It u tt u w 37 ta Smaktr Vs Ya Yrt Yrt Vr* ' Exjiaun DM jajr.taCu.it ' tO*l3U 34 JT. In O-ol. 1 17 jr. ta Pol. t TJ rr. In < at. I ' T-3ISS 71 n.tnCal. II 11 JJ TT. ta Col. Itl 4-3D-U 9) jrr.tnriU.il w tt. in I'fit l ' ii*33 a - TIjT.toCttLill <u Aotoptr T Y No v<* Yet Yet Ym Yc* HiwttrK Aflotlwfr To Yti Yf Yn No Nt choscopy with visualization ami biopsy. In would be very close to the 95% level another, although there was no autopsy, the of significance. However, having found just diagnosis of primary cancer of the lung 12 cases, we arc not above this level, and seems to luce been hcytiml question. therefore the hy|wthc#i.s that asbestos miners The term "suspected" primary cancer of do not have a higher mortality from lung the lung was applied to those in cancer than iloc.-i (In- general imputation can which the diagnosis remains in doubt luu not la: rejected Nevertheless, the occur some of the evidence |>oints to cancer of the rence of 12 cases in this sample would lung. There were three such cases. increase the rate n> a {mint which approaches lfic term "nuui-years of risk" has been the significant level, llccausc of the tre used to mean the number of men at risk mendous mqxinancc of the questionable for the year under observation. A |>er.siiit cases in this rcspcrl. nc detail regarding who lived throughout the year was counted them will be given liv. as a full nun-year of risk, but one who died In one of these cases, the suspicion of during the year was counted as one-half a cancer of the lung is based upon the x-ray man-year. interpretation, and, although no autopsy was Deaths occurring in the cohort, and in performed, the death certificate indicates which lung cancer is considered to have that death was due to lung cancer. It js been proved as a cause, are shown in Table well known that the x-ray appearance of 6. In Table 7 arc shown three deaths which fibrosis, csj<cci:illy if a localized density ,,r liavc Iwen nniMilcrcd as ">ns|icclvd" lung a suiHtrinqmscd tulnotions lesion is pres cancer cases. ent, ciin simulate that of a tumor, and by An indication of the importance of these itself, docs not justify the inclusion of this "suspected" cases in-interpreting the results case as one of "proved" cancer of the of the calculations is desirable before fur lung. A second case oas certified ns having ther discussion of the mortality rates which died by reason of liydmthorax, jmssilily ,|Uc arc dermal in later bilih-s. For example, it to lung cattivr. but again there was tu> liap|ieiis that (he rale found for the proved surgery ami mi postmortem examination. cases is close to the "expected" rate based In the third case, although it was subjected on the general population figures for the to autopsy, two pathologists disagrcvtl as to Province, as will be shown Liter, and on wliethcr lung cancer was present. Tlic death this basis we should find eight deaths from, was certified as having Iwen due to chronic lung cancer among the cohort. Actually, myocarditis with nephritis ami pulmonary nine cases were observed. If. however, the congestinn, and |mssildy cancer of the lung. 3 additional "suspecteil" cases were in On the hasis of these facts, it seems unwar cluded, increasing this figure to 12, the total ranted to include these three cases among TAtu.F. 7.--""Suspected" Pr!morn Cancer of the l.ang Coat Nt. 1 7 3 ACT It 41 a Snwkrr Yh Yrt Yn Ktpown l 33 >T. In Cat. Ill \ 33 jt, j Cot. Ill . 13 yr. InCol.il DM l(v-34-:n T- -Cl *-ao&s Anlopty No Trs No Atbtnoslt Nn Yrt No "proved" instances . other hand, they car. regarded completely, that mortality rate? both ways. Table 8 gives the r Tito, rates by Icnj. shown til Table 9. L' of employment, the tion which seems p were growing rider 1-ears of ex|jo.-ure : cases ro|xirtcd for a ing the six venrs, or of exposure. When, are added, one. case T.\mx s.--Lun-j C Ct SumScT of I'ctwm aal N m Orotic 3CMS.................... IS-M................. SV*............. AS+.................... Unknown......... ' Totally So.' t'cnc aw ussi Jt- J.Vi Annual Lunc Caanr Mio-lru, .Ur riuuu I'-n+k..u....m......-.......................................................... O.or-iU.......................... period. This would per KIO.OUO. again > portance of these proved, cases to because, if there w number of men with asbestos is a caretnog concluded that these strated considerable r> logical phenomenon w previously and is ccn. of an Intrinsic or end cer. The only other that the susceptible *group liad died earlier 18/ which appears Lit Ml t'oL IT, June. JOSH I Prattn--Trtuin rrrr- -1 WALT..lt. Al'Vi CANCER IN ASBESTOS MINERS "^proved" instance* nf lung cancer. On the " 1 -- -bihcr hand, they umtuit, in fairness, be dis- naii - Warded completely. It i* fur this reason v ' t mortality rates haw been calculated Mo NO ith ways. Vci <-- Table 8 gives the rates by age groups. 5 & The rate* by length of employment are t?ihown in Table 9. During the first -It) years \l employment, the rate rises, an observa- ^ Tv* ..^ioti which scents plausible since the men I 'cere growing older. However, after 40 "'.ant* Vars of exposure there arc no "proved" ""hm * I*46* rcf,ort^ fr a ttal of 240 men dur- n *un8 jj{ the StX years, or about 1440 uum-ycnr* n n'. ; jf exposure. When the "suspected" cases occur-.*; ire added, one case docs show up in this would j oaches e tre- Tacix 8.--Lung Canter Di'OMf by Agt Groups onablc Somber of Person* *nd Number of Lung Ciacrr Deaths trding 'ApOeottp No. of IVntbs No. of -- -- Pmous I`roved Total SJ01 umis at* a A.toS Annul Lung Cancer Death Rales per 100,000 MuvYrari of Kjt|r>urr Iferruup Prcsr 4^......... 7fskOOSRW . . v ... f the !| aving 1 OivreQ.. liw*l 4 U n 313 -0 Total 4 44 tl 3tt 0 94 v due itpcriiid. This would produce a rale of 69 s no -per 100,000, again demonstrating the imlton. ; portance of these questionable, but unected -proved, cases to the final conclusion, as to ; because, if there were no cases in this Icath number of men with long exposure, ami if rntc ijsbestos is a carcinogenic ageut, it must be nary concluded that these 240 men have demon- 1 grated considerable resistance. This is a bio war. ( logical phenomenon which has been observed nong j previously and is consistent with the theory H ,f an intrinsic or endogenous factor ill can- ==- cer. The only other explanation would be *<* that the suscefitible members of this age t |tnup bail died earlier of lung ouiieer. Talite 18, which apjicars later in this svetiuii. in Tabu: *1.--/.imp (Wt*/ JKutifa by fanylh nf limfiloytHt'nt XtnuWr of IVrwn* ami Xtnularr of lang Cawtr iVsfb U'ncth of Kni|ibyairm N<l of l>PUb> No. of -- - - - IVnons . I'ipvoI Tuts! A-.................. IO`|tl....................... ... w*w.................... ... 3U-99..................... .. 40*411,..................... S4-......................... I.7W l#m td eta 0 1 3 A. o. 0 O I 9 7 1 0 Twtab.... ... MS 9 19 Annual lam ft Cmcrr Death Kate* ivr 100.000 Mtn-Wtn of KtpMarc (nnlt of RmpW>*incut 4^..... ................ IO-I0.*................. . *KRI....................... 90-99.............. ........ .. . . 40-t8....................... +......................... OtcrolL Jtorcd 0 T M ]2A 0 9 IS Total 0 7 H 189 80 94 dicates that the members of the cohort did nut die from lung cancer at a younger age than the general imputation. The rates by weighted exposure are shown in Table 10, and it will be noted that they present strong evidence-against asbestos being a carcinogenic agent, for. if exposure to asbestos is in any way con nected to lung cancer, we would expect that the longer ami heavier the cx|*isure, the higher the rate that would be found. The only possible error in this interpretation could occur if the weighted exposures were inversely related to years of employment. Tasi.k 10.--Lung Canter Uatlhi by Exposure I'iili-jj.wy . Number of PUfld* tod Number of Lon* Oncer Ottib fUposun Cate|ury .. ferrm* No. ofDooilu Ifvreil Total 1.................... ........ II.................... in.................... Uakouwo...... ........ 9JM A 4 Q 4 4 4 a Total*~____ 9.BS8 9 19 Annual fame Oncer Drub Rale* per 100.000 MuvYurt of Eapoturc Eipnsuro Coieuory . Pravsd Tata I.................... II.................... V.............................. Ill.................... 73 99 91 IT 9 Uivr-ni) 94 mtt grgua--Tram 3 : i . .;* i i J f J ;i I 1 1 :> M r<** k V ; , i_ 1 . .4 .} .? ; ! 4 | i . 1 W i. i? A. M. A. ARCWITS or isuvstkial health LCNC CANCliK IN AS: Tails 11.--Nuinber of Persons in I'ariirUJ Wetghtei Exposure Categories by Length of Employment Wrnjtb of Kapto/manS Witold El(BIWf Caiiiorici 1 11 m 10-19 90-39 30-39 TOT ' 90 S IN 314 303 36 3U 79 or 34 - 31 490 Ul 3U 111 41 10 Tua 2431 3,190 Atincifnn tfupMtm 114 IU 1.773 184 - Un known 0 1 3 l 1 0 3 394 Total 1.195 14* 923 flta INS 33 9,931 174 in which case the heaviest weighted ex posure (Category III) woutd uKow the shortest length nf employment. Tabic 11, which lists the number of persons in various exposure categories by length of employ ment indicates that this error has not oc curred. In fact, the average numlier of years of employment for each exposure category is almost identical. Table 12, which develops the rates for , smokers and nonsmokers, is most striking. It shows that not a single case of lung cancer developed among the 1265 non smokers and that all rases of lung cancer, both "proved" and "suspected," occurred in smokers. Table 12 was mi striking licit it was felt that further verification wns necessary. It was possible that some abnormal distribu tion may have occurred, e. g., the non- Tablc 13--Number and Percentage Distribution of Smokers ami Nonsmokers by 'Ape Croupe Af* Orvup SM<................ . 4tt3-6-M4............................. "Teuls^ lunpili..... Number Smoker Nooamokcr ijoo 9 190 J3i 411 303 1M .3 130 0 1 u39n4 IAS 444 Unknown 13 4 31 1 30 40.1 1 TauLK 12.--Immo Cornerr f>raik fur Smokers and Nonsmokers Number ol Tcraons awl NonUi of Un| Caaccr tWv. bjr Snalim flabil* ,^ ftmokar* ............... NUnokiinitoiwwnk.f.n....^................. Totals........ rnom 4IA41S3 3JB59 No. of Death* PR>T*d Twl 0 Oa 0 9 Annual LunjoCf aEnxeptrotDore*atbhjrJiiUfotfo*kipnfrfr H10a0b,i0t*00 Mtiv-Yun No. of Dmbi Frond Total " ....................... Ugknwiu..... ....... OwatL.,, 0 34 smokers may hare included a larger jicrcentngc of young men. Consequently, ad ditional Tables. 13. 14, and 15 were con structed to show the distribution of smokers and nonsmokers by age, length of employ ment, and degree of exposure. Although there are slight differences, they do not account for the fact that all observed cases of lung cancer were in smokers. In respect to age (Table 13) the combined average age of the smokers was 4.9 years less than tliut of the nonsmnki-rs. Table 14 show, that as far as length of employment is con- Tablf. 14.--Number and Percentage Distribution of Smokers oud Nonsmokers by Lngik of Employment Employwent 3-9................... ... 10-19.................. 30-39................. .... 3049.................. 40-49..................... H-................... Total*..... .... Artnn toncth of employment. M,... Number Saukm Nomtsoken 1.4 3477 ra 119M9 1 79 a n I,3fi3 114 194 mo Talk IS.--Number amt ! of Smokers and ' ExpoJure l' cmwr l................. It...................... (,t`gitk.m...v..a....................... Total*...., (r^nMtiiwufv esusury...... .. Nuail* 'fmukrn U'4 ItA.SVS14 Un to rcrtcntaie Dlr.n fliiwMfre C*uoiy 6okr ; if:::::::::::::::::: l'ionk.<..*......o............................. Sis 3A.3 *yj. 1 Tout,....___ ~100% cerued, the smokers hat years less on the aver: smokers. With longer ex age. otic would expect i group to show Jflighcr were due to asf^stos. T the average exposure cc the same for the two r jlhis variable seems to t* in accounting for this d: The result of this ad that wmt ni thvtv factor the effect of Table 12. Comparison of the ; with that of the Proviiu minion of Canada, and ti In order to make a c experience among asbestc of the general population Quebec, statistics were f earlier, in the office oi . Table I> tvmmsfi DUtrtbudnn Acs Oreup Smoker Kotuiankcr Unknown SUM-M4............................................. M-4,,.................... t?nfcnoirD."-.-i...... . TateU.......... * Lea than (Uttft. 684 194 94 34 -I -- tcoft 1 544 IT.7 104 114 04 -- 1007, -" " 4 SkO 104 54 34 -- MS (`Cfccatncr IlldrUiulton Lonflh of EmpUijnwni 34.......................... 10-19......................... 30-39......................... XMtt....,................ 40-49..,.*................ +.......................... Titbit}........ Banker Xonsotoker 294 a.T IJ.T 13.1 3.9 14 ii% Unknown 504 104 304 04 uuy. froviim Cohort Trrootval 0 fl9i|l)t litcludlfit ubriioi fforken) Number of -- Peaoaj 1,191000 * 3,931 i.man |a A* Pmvutm fliurr*, tl hv * Approtluinlr wil|tnt f llw> rn.: ^Number *Ut to c*l*ri at W4I33I 144 Pot. IP, June, nst ; fraun-Tnan U-iYC CAXCBH LX ASUKSTOS MIXERS 15.--Xumhrr end t*UtriVtrfi*m tJ Smoker* and Xon*makers hy Exposure CiUtyry Huilii tiMtpxy Tout 1003 . 13 : fMnliti.uvn.. .. TotAb...... Nmitwr Smokm Setotuakvn 1433 <T Li.Aro4I US 1 5 to 14 ColiWITR 7t4o t 31 34 HW'Ycafi Cerctotati DlctrlliUiluo Total fjpmtre CU(otf . Saoktn \ .h::::::;:::::::::; ini...................... i (ikoota......... ..... su *u 304 04 too% NeamUn 91TL47 U 0.1 uoft Unknown 3&Q UB QUO Rented, the smokers had wurked alrout 2.3 larp.-r iy,nd- wars less on the average tlian the tumre con- 'gnokers. With longer exposure and greater mokers jige, one would cxjwct the nonsmoking eraploy- 7uroup to show a higher rate if lung cancer ttbough Isrre due to asbestos. Table 13 shows that do not 'Jiie average exposure category was almost d cases She same for the two groups. Therefore, respect i-his variable scents to be of no im(tortancc average ;iu accounting for this difference. ss than iSowi b con Thc result of this additional analysis is Lrtl ttour <*f them* faWfir.i a^a;ir> to Ictscti ,he jrffect of Table IX ` Comparison of the Cohort Experience tribution ttU lith that of the Province of Quebec. Do- tin ion of Canada, and the ('nilcd States.-- Jo order to make a cniu[eiri.-nn of the ikaavn M VX|>erieiice among asbestos miners with that ;^i the general population <if the Province of ^Quebec, statistics were gathereil. as stated 'jorfier. in the office of the Division of Demography in the Provincial Ministry of I Icaltli.. The data on total deaths, deaths fnini all forms of cancer, ami deaths from enoeer of the lung were obtained lv sex ami by county for the years 1950 through 1955. In midilimi. all death ivrtil'ualc.s which sjuvilied primary cancer of the lung,' and all those which indicated lung cancer but did not specify the origin, were cxaniined for the years 1952 through 1955. Table 16 gives a tabulation of the numlicr of deaths from lung cancer in the Province and in the cohort for the years 1950 through 1955, and shows the annual rate (ter 100,(XX) in lliese segments. It will be noted from the table that the mortality rate for the "proved" cases in the cohort is only slightly higher than the rale for the Province. When the "susiiected" cases are inehnlcd in Ihe calculation, the ratr for the cohort rises to .1.5.8 |kt UXI.OUU, which is about 50% higher tlian the.rate for the Province. This, it will be recalled from the previous dis cussion of the effect of the 'Suspected'' cases on the results, approaches but docs not exceed the significant level. One further interesting observation front Table Ifi is the rather marked iitcrt-a>c in die lotaf innnlier of cases for the Province between 1950 and 1955. It is assumed that at least |rt of this increase is due In intproved recognition and rv|mrliug of lung cancer during the interval. l;or this reason, the years 195-4 nm| l`55 were thought to le more nearly representative of actual condi tions. Even so, it is quite likely that the general (reputation is not studied for lung cancer with the same diligence with which tea known A oa *a OA OA --- 00% ' i 1 ` -- Taste 16.--Cuwfuriscn of Cohort with Province of Quebec Niunharof . IVWtt I83T1 1USI LongCamtof Oralhi tv* iwa rt*4 Annual Total lOMUO Vfio'tw* -f1 Tout . WtoTB itetttdlss Mbcstoy 1,190400 * 1433 f I.109JWO m 31 193 39 3 3 311 3U 303 e 0 - 4 3 3tt 300 303 1t ' 303 Iff 31 3M iftet 334 13 ' 334 9 1413 3L3 334 ' irbfD j |n flu (VsiviM* Iteurrs It hu< Imh Mmnml till mtif huif raww ilmllfi Ihf mifiar 3) ^ jraan, * * Apl^itiMto mM|ti|nt wf tlUMnusnuinl tM|<uisllun lur MU, Bfkl ito nUnuiH |x>ithUaa fur ^niibte). ,, (Sumbtr tllw In cutm o< l<tnnlag of 1923. iHuppntl. iMr. d b !>* \ ms trjun--frufln { <45 ''I i: i Vc i .1. M. .1. .miIII-ns OF IKOCSTRIAI. HEALTH l.l:SG i'AW Af Group 10-44 <1>M IV44 Totals *Taw.k H.--}.ui>9 Cnin (Miu Jut IHe 1`Torintf r>J Qnrfctf *' Ityutottat T7T^i vasnt USJ*i 131 AW NunUr of Dcidt \V4 TmihI rnw civrlfliM IviuufT Total TuUu |*nirv4 11 47 11 Hi It 41 0 ru IUQ III 3* a . 91 39 2W IVl :>v Tttlul I'rriibxl Total I'mvw T-ItU IT 0 ill 35 11? 14H . 17 116 140 313 l$S xn 1'uttizry lYntJ 9 31 1? M `W . Tan.*: <* I An* 3 it.............. AAJM+*................................. TuUi....... Ha|f*n. it>94. Dtttk Raki fwr 100,000 IVM * ISOS a mailer or as if is in vi At* Oranp SH4........................ .. 4641........................................... .................................................. 96+...... .............. ~.................... owu....,............................... Total CmlflrdSprrtftrU lYtmarj- Total CVrttflod Tubal ITrvpiI Total I'BIfAl Total 3.9 334 73.0 1.7 1.-4 17* 314 37.7 30.4 14 14.4 9.4 2.3 20.7 M.I 01.7 374 *04 344 1334 04 0.7 14.4 <4 37.4 gpottftod 1`rirevy Promt 13 174 414 444 Hi ToUl 34 37.1 04.7 1334 974 frond UA 4U 444 134 Tabic IS viously raistof the volum ccr at an age . latiotrrand th : be offered f * llita (rain dmdt mHOnini. t 6* puraliifn oUalneil toy atn*7tac IW ivrrontaeu to at# fnjap* to main to Iht l4ai fpitaUon to 1954, 3t ttUn la JUpport, Plv. dr to iVtewsrophlc. .* this disease is looked for iu the miners, and . it seems probable that the mortality rates for the Province may be low. This would appear to be substantiated by the fact that the reporting ot cases in the cohort showed no such increase over (he same period. _. Table 17 was compiled to show the an nual agc-s{iccific lung cancer rate of cases in which the death certificate merely read This cimi|iarisun, MUiitnarizcd in Table 18, shows that the observed number of deaths in our sample is not significantly greater than the expected number of deaths, based on the aremge of the 1954 and 19jj figures for the Province, ft is true that, in the case of the age group of 65 and over, the five deaths provide a figure which is almost significant at the 95'-i level. How ill 240 men employment Before lc:. Province wv shown that '. sociably the : be observed It should : i retire and cI that the ol<K t j the general ) in. Table 21- "cancer of the lung." as distinguished from ever, it should be-noted that this number rate generall; those in which the diagnosis was confirmed includes one of the suspected but unproved fore, we coi:' by autopsy, surgery, or biopsy. The term"specified primary" refers to those cases in these two categories in which the tumor was specified as having originated in the lung. It will be noted that, of the total cases reported in 1955. a much higher percentage cases previously referred to. . Furthermore, it is rather likely that the rate for the general |H>|>iil:itinti is understated in this age group, for tlie obvious reason thai'thr exact cause of death in the very old is not over 65 to 1 group betwci to the oldes that by us::: tion, we h.v. era! popular than in 1954 were specified as primary. The table also shoves that a higher percentage of the total cases certified in 1955 were proved, again indicating increasing interest in this disensc. A comparison has been made between the age-spccifie rates shown in Table 17, and those for the cohort, shown in Table f. An average of the 1954 and 1955 rnte^ for the Province has been used, since the 1955 figure was higher and may have Iwen ex ceptional. Tabu: 18.--Companion of Ifte Achut! and F.jrfcctrd Number of l.ung Cancer Dratht by Age Among Atbetlnt SIinert frovlnru Tnlol Prlitmrjr Mat* Group |*r UI4A> 20-44 5*M iy*4 UnVnowA 14 214 S74 094 RtnvfH S'u, f No. of l l*a<bNfo Mlttfro 1 lentil' Pm*til xtn 3401 1,013119 913 9 ot 3 3 ..3 loaaTnV(r4rMi*TWlfVIr'tlluttlHl'siHAlnv*|Wb lCrmtlvohtsrit*f fItfvimeralacot.of Uu IQai im^ | Actually U.t. than if we people in the ' A compari and the f-oj whole was : from severa. lips19 gave Canada for 1952. The Table 20. These figr in ratesbe! 646 I'ol. IT, June, mj Braun--Trw.n WAL HEALTH IlVXG CAXCER /.V ASMiSTOS MLXKRS Bptdflad Primary Toul ProTd IT M ui tu a H M* m 4 Table 19.--Age Distributum of Adult Motes fee : the Province of Quebec, 1951 $> ~ `i Af. On.Jp - hortncf Sultrier IVmttiag* In Culutft J-t*.................. (M4.................. SK*................... 71I.IU .. 43 IMBJUS -.19 191.9*4 II 113,467 10' . (A Toul- 1,149.496 IU) 100 JUppon, ISM. i matter of the same intensity of interest as it is in younger persons. Table 20.--AtuttutI Dent!i Rates per lOOfiOO for Cancer of the Lung in Canada0 Onwpi ot Y<ar Set itroup 1141 1933 (MI-1949 ttalrr.SO 04 30-34 - oJ 33-39 40-M ' 'fit **-*9 44 S>34 14 A3-59 . IU 6D-W ' IU 40-00 IU 70-74 to.? 73-79 UJ 40-M 94 IH 11.4 AO Aset u 04 04 34. lA 134 ' 114 314 XU 344 304 304 774 144 74 ' ._ loao-tvs? 14 04 94 94 IU 374 39.7 774 1014 094 934 39.7 714 134 Bptrtflod Primary Tool Pmid 13 .T 4.7 u IU 4U 4U OS Table 18 also answers a question pre viously raised. It shows that the members .1 of the &hort have not died from lung can- i cer at an age earlier than the general popu lation, and .that such on explanation cannot (jbe offered for the absence of lung cancer " jin 240_men with more than dll years of Uaa(DrlSM,utir. 'tmiplnyment rcferrnl toon |ko frl.l. * "Mortality Cmta l.uaf Ciwn In 1931 U 1939. increase is particularly marked after age 50, confirming an observation previously made, to the effect that until recently lung cancer has probably been underdiagnosed in the older age groups in the general popu- ' ^ Before leaving this comparison of the Hzed in Table i Province with the miners, it should be. ted number 'of 5 shown that their age distributions arc rea mt 'significantly 4sociably the same. That this is the case can mber of deaths, ^be observed from Table. 19. 1954 and 1955 1 It should be remembered that the miners is true that, in ^retire and consequently, it can be expected if 65 and over, jihat the oldest age group will be larger in( To use these figures for puqioses of comparison, it is necessary to combine the rates for certain age groups in order to conform to the age distributions used in this study. Since the exact populations in each age group for the years indicated is not known, this must be an approximation. However, the rates would be somewhat as figure which is (the general imputation. The tlata presented Jb level. How- in Table 20 indicate that the lung cancer iat this number rate generally decreases after age 70. There d but unproved fore, we could expect the rate for all people . Furthermore. over 65 to be smaller than the rate for the C rate for .group between 65 and 75" which would apply follows: . Ace Croup 20-44 45-54 55-44 <5+ Rili 5 27 69 *' 90*91 These rates arc, in general, lower than TStated in this ,he olJcst gtuP oi miners. It is felt those developed for the total (proved and reason that the that by using the whole adult male popula very old is not tion, we have developed rates for the gen eral population which are somewhat lower suspected) cases of lung cancer among the asbestos miners. The only large difference, however, is in the age group of 65 years and the Actual and atg Cancer ueng t than if we had been able to exclude the people in the general population over 75. A comparison between the asbestos miners and the population of the Dominion as a ' . ObMmdHo. jtcua or Death. the* rrawd .Total 5* t \\ .. whole was made, using statistical material from several sources. In one source, Phil lips1* gave age- and sex-specific rates for Canada for three periods between 1931 and 1952. The rates for males are given in Table 20. . yentt 0 th IWu4 (llMhK. These figures show strikingly the increase jin rates between 1931 and 1952, and.this over, and it is quite possible that the rate for this group ntay have increased for Canada between 1952 and 1954 as it did for the Province of Quebec (Table 17). A further emtqiarison has been nude-with an over-all rate obtained from the American Cancer-Society for respiratory cancer deaths in Canada in 1953. This rate, for males. Is 20.8 per 100,000, or 5 more per 100,000 than Phillips' 1950-1952 rale, and compares' with 25.3 per 1fX).OCX) for proved cases and 33.8 per 100,000 for total cases among the rol. IT. Sunt, Jp.tV < $raun--Trunn `i A 1 ;wt; r 7 jr-WH vatVgEtV. JBftyAg'. ..-..a.*,-. . .. --......................-r, ... . V. fc- .1 ' vKj r *- (J Is: * ^ b * v; i*. Ti-' -4* .1. m. ./. am turns <>r ixtx stki.ii. iih.ii.th IA At.' ( .t.Wl.r ' 1'aoi.K 21.--Sumber of 1 l.'iillu auJ 1 KmIII tiolex fcr UV/HJQ Oy el</e limtifs fur site ehlttlt way, ami other eotmtrivs. at least Sd.tXXt Male /`ofufuliun of the United States * persons must be exposed throughout the Taih.i .world, and it can be assumed that this Ak Oroap 8M 4M4 tHi + . tapubttm tAuu* Car wim Ku |rr im.uo a. mj tig number lets Invu fairly constant in the 20 years siiav 10.15 when the first rase of asbestusis with, lung cancer was reported. ('tutnivt I's.utst r fKUttdfhlitl ".Vl^uviCti h' itiiVp.;. PrurlniT h| TstoJ \*JW IM At least l.OOO.OUQ man-years ol exposure flttvlnce *4 l|ttrivc |r*3 "isIhtTiM" o'trii** has tints been accumulated, and this figure Jjtfntrrjl M lilt lr * Data from -Vital guitxfctf el tho Colinl Elates,** V4. | can be divided by the approximately 150 || b)MinM>| :tjui a cases of lung cancer with asbestosis re asbestos miners in this study. It is there ported during the 20-year period. This fore obvious (lint tlicrc arc no iiu|inrtaiU gives a rale of 15 per 100,000, which is at' immediately sur differences between the rales for asbestos least indicative (hat any lung cancer rate during arras is) miners and those for the general jiopulation which cau ho calculated for workers ex- of eight countie of Quebec ami the Dominion of t amnia. (siscil to asliestos dust is not much greater While Mrgantic Since it is proliohU: tluit figures for the Ilian dial for the uiiexposcd population. twice tluit of it United States arc mure complete and, there fore, possibly more comparable to the (lata for the miners. age-specific rates were com Comparison Hrtruern Eiffht Counties ,{J. jacait to the Asbestos-Producing Areas and counties7 it is !<. : Trovinec. and c rate for Montre: puted from "Vital Statistics of the United Stales," Volumes f amt II. for IV52. These rates have been tabulated in Table 21. Eight Selected Ceiinties.---To compare lung cancer mortality rates in the counties sur rounding tin- asliestos-jiroilneiiig areas with would certainly very low uuiuIk 1950 ami l`>51, It is apparent that these rates compare another group of counties in which no as in those years sc favorably with those for the asbestos miners bestos miners arc likely to reside, the rates undoubtedly beer, as shown in Table & Still other rates for .were computed oil the basis of figures far other years. 1951' the years 1950 through 1955. The eight the United States were obtained front the . counties selected for coni|iarim were Ar-' American Cancer Society, and for males, cx|cctcd to be would result in ; these were 25.3 |r KX1.000 in 1053. and gctilcuil. CUalcaugay, Moutmaguy. Port- The only pof 2S.0 |er HlO.OtKI in 1*155. They are' not ueuf, ktehlieii. Uivivrc-du-I Jiup, St. comparison is lh: ideiitieal with the rate ealculaled from the figures of (he office of \Ttal Statistics, but ' I lyaeiiitlie. and Terrelioiiue. mainly because they represent a wide geographic distribu the. persons who ties surrounding this is possibly because the American Can tion thrnuglNitit the Province. The counties bestos-producine cer Society rates arc for males of all ages. selected lierausc of their pmxiutjty to the 1 incidence of lur. Nevertheless, they, too, comjiarc favorably astxstos mines include Arihnteiska, Beauce, | live elsewhere, in with the rates of 25 for 34 for total cases) Drummond. I'mittcnac. Mcgnntic, Rich ; C'OiiHi,^* mi . obtaining among the asK-sins, miners. mond. SlterliTooke. and Wulle. Table 22 Ciites. /y/iiu un- Tumittg for a moment to a comparison shows the nutnlier of lung cancer deaths, tos Miners.--Alt between the asbestos miners and persons for the years 1950 through 1955 for each tinu of all the kr. who are ex|>oscd to asbestos in one form of these counties, and a mortality rale, cancer of the lu or another (as distinguished from the gen based on the adult male population in 1952, particular value : eral population groups just discuscd. who To emphasise the comparison. Megamic view, it is of in have no exposure) an interesting observa County has been shown separately, as has cases for the reco tion van lie develojied by dediietion. 1 (ne the Province of Qoeliee ami also the Prov prior to the lieg) per** lias staled that there arc about J5.IKXI ince with tlte eight "asliestos-prgiluciiig'' covered by the stu persons exposed in the United States, and counties subtracted. Because ol its unique the diagnosis wa we have found that the Canadian mines lung cancer death rate,. Montreal el I Me dt coma. During lh employ almut #000. Klsewhere. it has been Jesus has also Kvn listeil in onler to provide investigation. the: estimated that the workers in l-jiglaitd who * lurther cnm|cirisiiii. and three siis|ha have exjutsiire total U'lunn 3000 and 50011. It is apparent from the table that pie Thrnui^h IPJfi ai With workers in Africa. Denmark. Nor-, lung cancer death rale (or the eight counties were eight deaths. MS 1'nf. IT. Jane, ftfx Proun--Triton ' .l 'segy <ji* t*> 1 TRIAL HEALTH \ll'\C CAXCER IX ASBESTOS MIXERS at least 50,000 Taiut. .Vumtirr f /.< t'iu,vr /V-cffix nut/ Halt f,r J/jo-t'.-u throughout the unted that this istant in the 2d first case of was repotted, rs of exposure and this figure Count kt VUtattlU CountT ,Cubt MAdJrtmx| ' Uftil Mitdi (Wtb piortnro girWe fiovtncr of VuHwc lr*r(ht **MtkKvnlM mttiitlpi SlimUral et Wo tfa Jn Adoll >ljb hutufeiltua IW2 13. KM *3.1*11 MIMO 3V4JIX) \KC 3 1 3 1`*. (: 3 19M 1 a lit VJD sir T Matt lunif Cautn Ifr-atlti * wt l*S *4 wa .Total a . a t 4 li ti 4 314 14 u so 1 3 30 hi V u; - 49 l(Qt sw IM *3 (93 l*S 341 ns u7e7o0 lLitii\ltr|<vtf- 1.t (M P. 33-fi SL W-1 roximatcly -150 It b atatrac4 itwt oil nlr Inn? canm itruitu H*tunv*l (trr at* 3k asbestosis re- period. This inunedialcly surrounding the nsl>csios-pro- suggestive f cancer of the hmg and in )00, which is at ducing areas is practically identical with that cluded such diagnoses as mediastinal mg cancer rate i 0( eight counties selected for comparison. lyiiiphosarciHtia. mesolhetimna, cancer of die r workers ex- . While Mcgiiniic County lias a rate nearly leg with iiK-tasi.'ises to lung, abscess of lung, t much greater ; twice that of the combined eight selected and cancer of the jiancreas. One other was d population. -j counties, it is lower than the rate for the diagnosed on the basis of x-ray only. In it Counties Ad- ' Province, and considerably lower than the addition, there are now living four cases in icinp Areas om; irate for Montreal. The figure for Montreal which the diagnostic evidence is strongly o compare Inns ' trould certainly be higher except for the suggeslive.of lung cancer. This is a total of c counties stir- wry low numbers of death* reported for 33 cases of all tjrjies, including 1(1 "sus clng areas with : 1950 and 1951, anil it would appear that pected'' but unproved cases, and 4 that arc n which no as- . in those years some error in reporting has still living. The remaining 19 constitute the eside, die rates undoubtedly been made. On the basis of the total of proved cases of cancer of the lung of figures for ; other years. 1950 and 1951 deaths would be among the asbestos miners since 1940. *55. The eight ' expected to be about 200 greater. This The proved cases averaged 59 years of rison were Ar- "would result in a rate of 40 per 100,000. age at death; and varied between 37 years tmagny. Port- j| The only possible conclusion from this and 63 years. Their working span covered dti-Loup, St. .(comparison is that there is no evidence that periods varying from a minimum of 14 mainly because jthe persons who live and work in the counaphic distribu- |iics surrounding and adjacent to the as- The counties bestos-producing areas have any greater oximity to ih,; ijincidence of lung cancer than those who ibaska. Tlcaucc. five elsewhere in the Province. egantic, Rich- Comment on All Recorded Lung Cancer '^e- Table 22 ICorcr, /.hang and iL-ad, outrun/ ltic Asbes- cancer dcauis il Miners.--Although a simple emmicra- 31955 for each lion of all the known or suspected cases of mortality rate, Jancer of the lung in these areas has no Uation in 1952. (particular value from a statistical point of son, Megantic ;erw, it is of interest to summarize such irately, a$ has j cases for the record. There were nine deaths years to a maximum of 37 years. Only three men had less than 25 years of em ployment in die industry. Seven among those on whom such information Is avail able had a weighted exposure placing them in Category III. ami six worked in an exposure represented by Category I. There were only 17 among these proved lung cancer cases in which we have in formation regarding the presence of as bestosis. /Asbestosis was present in nine. although it was minimal in two. Two |>ath- also the Prov- iPr*r,r to the beginning of the time pcrimI tos-produeing" !cVl`rcd by the study, including one in which of its unique !the dia6nosis was mediastinal lymphosarreal et Isle de jcoma' DurinR ,hc Pri<vl covered bv this ologists disagreed regarding ils presence in another. At least seven of the 19 p[iroveed 'lung cancers, therefore, were no`t accom panied by asbestosis. rder to provide i'nvcs,iRalio"- ,hcrc wcrc "i,w proved cases .j and three suspected cases in the cohort. table that the 1T1,r<,uJ4fl 1956 ami to date in 1957. them eight counties j"m` six which were merely 1 Summary and Conclusions Interest in the (picslimt of whether there may be an association between lung cancer -1,17. June. 1959 U'^-Tman -to1) II ' I t: ' i f 3i A. M. .!. .m iin ns oi- ixnt 'STKi.ii. hhai.tii /.( *(; C.WCEK and cxjxwurc Co asbestos lias been evident was imt pissildr to trace 1.1.1 of these for since the report in 19J5 by I.yncli anil Smith (lie whole period, hut 5771 of the remaining of a case in which lung cancer and asbes- 5958 were found to lie still living in 1035 tosis were both present. As additional cases or later. Of (he 187 known dead, cancer in which the nvo diseases coexisted were of the lung was considered to liave bcvii reported, a eaiisnl association ap)tcars to reasonably proved in and to tic strongly liave been gradually accepted by many suggested ill 5. authors, although some' workers considered The members of the cohort were studied the correlation to be inconclusive. The pres with respect to age, length of employment, ent study was undertaken in an effort to de a weighted average of their exposure, and termine whether a causal relationship slid, their smoking habits. It was found that in fact, exist between exposure to asbestos 4675 were smokers within the definition of and cancer of the lung. that term as used in this study. Thirty-four Since most earlier studies had lcen ' per cent of the cohort were oiorc than 4$ limited to enumerating the lung cancers venra of age, amt thirty per cent had been found in certain selected samples, such as employed for longer than 20 years. Thirty cases coming to autopsy or death certificates per cent had a weighted exposure which in which asbestosis was mentioned, it was placed them in the category of highest ex apparent that they could not fulfill the re posure. quirements of an epidemiological and sta tistical approach to the problem. The present study was, therefore, designed to meet the requirements of this method. After a preliminary survey to explore the availability of reliable information, data were gathered an workers in the asbestos mines in Quebec, based on their medical records. A cohort was defined as a group of asl>cslos miners liaving at least live years of exposure and who were in the industry in 1950. Data relative to their characteristics The mortality rate for lung cancer, n, computed mi the basis of nine "proved'' deaths among the cohort was 25.3 per 100. 000. When the three "suspected" cases were added, the "total" rate for the cohort rose to 33.8. The iui|xirt.iuce_of the suspected but unproved cases in determining the,e rates has been reiterated because it is likelv llmt such cases would not lie included in the statistics for the general imputation and because they Influence the results so mark edly. were collected and .their status at the cud of a six-year period of observation was de termined. In the case of those who had died, an exhaustive search of death certif According to the findings in this .study, the mortality rate from lung cancer does not appear to increase with length of exjsisure or with degree of cx|Hisurc. a fact icates and insurance records was carried out which presents strong evidence against the in order to determine as nearly as possible carcinogenicity of asbestos. the exact cause of death. Mortality rates Comparison of the experience among the from lung cancer for the general population asbestos miners with tliat of various seg of the Province of Quebec and its various ments of the uncxpbsed. comparable popu counties and for the Dominion of Canada, lation shows that the observed number of as well as the United States were calculated deaths among the minors is not siguificatuly from statistics collected in the appropriate greater than the exacted number. The rate places. Comparisons of the rates obtained for proved cases among the asbestos miners for asbestos workers and for the other popu (25.3 per 100.0001 compares well with the lation groups were made according to ac rate of 22.5 |icr 100.000 for the rest of the cepted statistical methods. ' Province, ami 20.8 per 100.000 for adult Records were obtained on fiOOl persons males throughout the Diuniuinti of Cntimki. who fulfilled the criteria of the cohort. It It also cnuqiarcs satisfactorily with rate* ..f 37.2, 25..V and 2 sources for adult n: Finally. in this n: would appear (ha; i of jkt.mmis worse with re>|*rel of the unvX]Hiscd The counties su producing areas, i: most of the asbest most identical nwrt: tight counties wide Province, and are I remainder of the Pthan the rate for M Since -I9-U3 there which the diajii> the lung may be c proved. ApproximTt were associated with died in the rveugniz least one-third had posure (Category I On the basis oi complete and relhbh conclude that the : Province of Qurbec icamlv higher ikath than do comparable : jopulathm. Furthcnnore, the cancer in the areas c ids o|icialiiuis is erm: widely scattered thro Ouelicc and is Iwviized areas within the refe: I. Abfch. Escobar. I Review of 200 Casts, .f y>:375-.\r*> (Sept.) WSr 2 Allen. M. L.: Bm. l*dnlfil wiilt Pnonmu lascs. .1. IihIiisi. Hjv. I< J. Cartier. P.: A G -if Asiwsiosis, A ret r |49. 4. Anderson,. C. S>- ai au) Carcinoma of the I l March) PtM. ' 5. Ila.-id.-r; I!. W.: A iVv'lmxhr. o5:407-liV i 650 I i'/. IT, Junf, J9if Jri/iui--Truun I'.ILTH *IVXG CANCER IX ASBESTOS MIXERS sc for 'mining n 1955 Jif 172,25.3, and 28.0 obtained from various ipourccs for adult males in the United States. ^Finally, in this uutter of com(iarison, it cancer J been rongly ' aould ap(icar that the world-wide experience if persons c.xpo.sctl to asU'SIns dust is not rorsc with rcsjscct to lung eaitcrr limn that - d the unex|*)scd imputation. tudied vment, i. and 1 that ion of /-four an 45 - been Thirty which 't ex- . The counties surrounding the asbcslos'producing areas, in which it is presumed post of the asbestos miners live, have al most identical mortality rates with those of 'ight counties widely scattered through the .Province, and are lower than those for the Remainder of the Province, amt much lower yian the rate for Montreal. .j Since 1940 there have been 19 casei in phich the diagnosis of primary cancer of he lung may be considered to have been Moved. Approximately half of these cases rcre associated with asbestosis. AH hut one tint In llu* recognized "ismccr-agc" ami at least one-third had only the lightest ex- re (Category I) to asbestos dost. On the. basis of what arc believed to be ,, iplctc and reliable data, it seems fair to pjndude that the asbestos miners in the province of Quebec do not have a signif- sanlly higher death rate from lung cancer hail do Comparable segments of the general '/ioiiuUition. * A Furthermore. the death rate from lung Tiitcer in the areas contiguous to the asbes- ' lis operations is eninpaRihle to that in areas -jridely scattered throughout the Province of flucltcc and is lowvr than in some urtmii- id areas within the Province. REFERENCES I. Alascio Escobar, K.: Bronchial Carcinoma: Irriew of 300 Cases. J. Internal. Coll. Surgeons >J7S-379 (Sept.) 1956. j i Allen, M. L.: Rrunchiogenic Carcinoma AsViaTcd with I'nninioni vnuiosis: Rri>n of J (no, J. Imlnsl. Ilyit. 10:346-347 (Nov.) 1*134. A Cartier. 1*.: A Contribution to ihc Study : t Asbcstosis, Arch, mat profess. 10:589-595, .'449. ` A Anderson. C. S.. ami Dibit, J. 11.: Silicosis 3>J Carcinoma uf the I.uii)!. J. 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A.: Dronrte.- liuiiiciry SIoi (4 Tool (nr Treiinir Tlworic* of Cimrvr Flii..1.v>', couc (i.r.ii*.-na in A-sorlniUin u-iili Pulnvaurv 19.15. Am. J. Puli. Ilralili 45:615-621 (May) 1**55. AdcMiei': He|irt ol 2 Cases, Am. J. Path. |g. -j 65. l-atiea. 32. Egbert, D. S_ and Geiger, A. J.: Pulmonary 122-135 (.lau.) 1942. ' . j New York an Asbestosis and Carcinoma: Report o( a Case with 49. Hombnrgcr, F.: The Co-Incidence oi 1928. Necropsy Findings, Am. Rev. Tubere 24:142-150 Primary Carcinoma of Lungs and Pulmonary j 66. I.eiv. E. (July) 1926. Asbestosis: Analysis of Literature amt Rrpirt ! panv Kivnnls 32. Ellman, I'.: I'nlimviary Asbestosis: Its of 2 Cases. Am. J. Path. 19:797-807 fScpt.) PM3. i Imhi-4. ilrg. Clinical, Radiological. amt Pathological Features 50. Horn. 1>.: Is Lmig Cancer on the Increase* J 67. Linsbae. 1 sad Associated Risk oi Tuberculosis Infection, ' Evaluation <i Present Day Eviilence: Cancer nj J. Indust Hyg. 15:165-182 (July) 1923. llic Lung. l'osa-otings oi Stic Sricmific F.ccm r. patiunal Cane paili. Anar. .1 34. Ellman. P.: Pulmonary A.dicslosis, l'nt Roy. Soc MciL 34:557 (July) 1941. 35. Feil, A.: Pneumoconiosis in Asbestos Workers, Prcsse mid. 39:1872-1874 (Dee 19) 1931. 36. Fulton. \V. B.: Donley. A. j Matthews, J. L, and Huutz, R. L.: Asbestosis: Part 111. The Effects o( F-xposure to Dust Fjicountered in Asbestos Kaliriratiug Plants on the tlmlih of a Group o( Workers, Special llidktiu No. 42. Pennsylvania Department of Labor and Industry, Bureau of fndust Standards, Sept 20,. 1935. 37. Gardner, L. U, and Cummings, D. E.: Studies on Experimental Pneumoconiosis: Inhala tion of Asbestos Dust; Its Effect upon Primary Tuberculous Infix-lion, J. IiuIusl- Hyg. 13.-6S-81 (FcK); 97 (Man'll) 19.11. 38. Gilliam. A. li.: Mortality Trends in l.iing Cancer. Cancer 8:1150-1136 (Nnr.-I)ce.) 19S5. 39. Gilliam, A. G.: Mortality Attributed to Lung Cancer in the Large Cities ol the United Slates in 1948 aiui 1949, J. Nat, Cancer Inst 15:1307-1312: 1955. . Annual Miviing. American Caiuvr Sncieiy, Nov. .4-4. 195.1. 51. Hoeing. F.: Clinical Considcraiinns <i d* Qoestiim oi Imlusttial Cancer ot .Asbestos Work ers, Ztsdir. Krcbsfnrsdu 47:281-287, I9JS. 52. Iluvpcr, W. C-: Cancer in Its Relation t6 Occupathsi ami Environment, Bull. Am. Ssi Gsilrol Cancer 25:fd-fi9 (June) 194.1. _ 5.1 llik'ivr. W. C,: Significance oi ltnlii>mU C-anver in tin: PnMcni n( Cancer, Occnp. Mri. 2:190-200 (Sept.) 1946. 54. Harper. W. C: Enrinsuucmal ami Occu| j. ihaul Cancer. Public Health Service. Sitpp. *o' U. S. Public Health Sen-ice: 1949. ' 55. Huepcr. W. C.: A Metluriology i< -r F.nnrui. mental ami (icvuivilustal Cancer Surveys. f-u)yc 11,-nlili 3l*a^r:i|4, X.I, I*. If. 8. I'ul4iraih.a No. 12. C. S. I'nldie Ilralili Servhv, 1950. 56. llutys-r, \Y. C: F.iivironmcnlal Lur.Oinecr. Indnsi. MnL 20:49-62 (Feb.) 1951. 57. Harper, W. C.:. Ocrupalimial ami Fjyvirir.nwntal Pnliinaiary Canrers with Special Rciciece to Pmimas-iniosis, l'n-iv<lings, 7lli Safari- 6S. f.yucli, monary Ash. Aslesto-Silico.1935. W. Lynch, nvoonry A.-les cinnma ami .16:567-57.1 (A 70. I.yneli, ) to#is: Amilysia 14:874-889 (X 71. McPhce: oi Employees Imlnst. Hyg. - 72 Mcrcwei: fiiln, ,t:i ry Kit liixi- ill A-U-l'<tt t May); 2 7J. Merc well Report cm F.fiiand I lust Sup; f.ontliMi. Hi* 2 40. Gloytie, S. 11.: Two Cases of Squamous Syiit|ai>umi isi I'lW.nmi'cisiinsis, 1952. 74. Mcrcurrtl. Carrittotna of tlur f.tmg Occurring in A<l<-insis,' 58. Ilne(-r. \Y. C.: A ijin-d into tli,.- Envirr,.- A.-ls*>tosi-.. Tl: Tubercle 17:5-10 i<M.) 1925. mrnlal Causes oi Cancer of the Lung, p^ 152 l Tan.) |9.' 652 lul. 17, June. |tj J't.iint--TfiiuK t<.y%*5ir<wr7,'.T .77/ 1 it-'.Vt; C.lS'Cl-R /.V . ISflESTOS MIMIKS llto***. Health Monograph No. 36, |`. ||. .S. I> > ,Vn W4 U. S- Public Health St>ht, 1055. 59. lluciicr, W. C: Environmental Causes of ^ar- Cancer of the Lime other titan Tobacco Simdcc, *ii. i Oi*. Chest. J0:14l-158 (Aug) (A IsH'll-adtcr. K. .1.; Kbits, H, ml I lardy, A.; II. I..: Asbestnsis anil Hnmrluigcuii: ('arcinuttta: 10 KciHirt. of One AtiUipxicd (iasc ml Nrvtvw of *'*. Available literature. Am. J. Mol. 15:75I-7J5 t.S'uv.) 1955. - In Ol. K cutaway, E. I-, and Kcuuawny, X. M.: A in- Study <>( the Inciilcnrc of Cancer of the l.ung A. anil larynx. J. Hvg. 30:2J6-267 (June) 1950. & Oi Kamaway. E. I., and Kciuiaway, X. M.: Simlie* of Incidence of Cancer of tlic l.ung and oI Larynx. Brit. J. Cancer 5:155-158 (June) 1951. tfth ul. Klotz, M. O.; Anorialiin uf SilinMt ami Carcinoma uf the Lung, Ant. J. Cancer J5:38-49 i tn* (Jan.) 1959. *54. 64. Lama, A. J.; McConnell. W. J.. ami Fetmet, nic , j J. \V.: Tlte Effects of tlic luliabtiun of Asbestos Oust nn the Lungs of Ashestns Workers: Pre .to- > liminary Study, Pub. Health Hep. 50:1-15 Vfan. 4) ary I 1955. ' ' 8: . to. I.aura, A. J., editor: Siliiisit and idr-ltaU, New York ami Luxlnn, Oxford University Press, of 1958. . "T 66. Lew, F. A: Use of fife Insurance Com on pany Krrvnls for Cancer Studies, A. if. A. Arch, < .5 fmlttst. Hyp. 5:198-305 (March) 1935. . * 67. Liiizlmch, A. J., ami Wedler, If. \V.: Utii- o| patimtal Cancer among Asbestos Worker*. Arch, path. Anat. 307 -.387-409. 1941. 1*8. f.jnrli, K. M., ;uul Smilli. W. A.: Pnltmemry Aslicstosis: Cnrciiinma ul I.unit in he Astcsio-SiKensis, Am. J. Cancer 34:564>4 (May) 19.15. 69. Lynch. K. M., and Smith, W. A.: Pul to monary A.iln'iuvlt: A Rvp*rt of Rruticldal Car- cinmna ami Epithelial Metaplasia, Am. J. Cancer 56:5*7-573 (Aug.) 1959. iU , 70. I.tttch. K. M,, ami Cattumi, W, M.: Aslicstosis: Analysis of 40 Xccropstcd Cases. Pis. Chest ;* 14:874-889 (Nov.-Dee.) 1948. 4* :! 71- McPhccIcrs, S. B.: A Survey of a Group V* of Employee* Exposed, to Asbestos Dust, J. I Indust. !Iyg. -18:259-339 (April) 1956. O- ! 75. Merewether, E R. A.: Tlte Occurrence o( he ' Pulnmuiry Kil*ro>is and Other Pulmonary Alice- "**-i imis iii A4<m \Vnfkrr\ J. (mlnM, |(yg# 12: W < May) ; (Juim) WJ0. i 75. Mcrvwcther, E. R. A., and Price. C. W.: Krport on Effects of Aslicstos Dust on the l.ungc ami I hist Suppression in the Aslicstos Iiulitsiry, London. JI is Majesty's Stationery OlViv'e, 1950. e * J 74. Xlvreuyllicr, E. R. A.: A Mcmoramliun on A-t-slimi. TuUwvIo IS:J0(>; (IK-,-.) I'*.U; 15: 4>.-i 152 (Jan.) 1954. I Frutin--Trturn I 75. Mi-n-wciht-r, I-'. It, A..- Anined lsc|->rl.- <( tlte iVtei Inspector of Factories. I.oitii.,0. Ills Majesty's Statiumry t tliier, 1947. 7n. Xlcrctwilier. . K. K. A, editor: Industrial Mfilu-iuv' ami lliginte, I a od< lit, llullvrtvorlll fc Co., lad., 1956, \ ol. X 77. Xonlnenni, M.: Tlte Imhislri.-d Canevr of Workers in AsU-stos, Zix-ltr. Krvli-t'oreh. 47:588 305. 19.1s. TX. Xordttuum, XL, ami Sorer, A.: I'nlnhstary OuuTr Produced lsy Aslrstos Uu-i in Experiniciual Animats, Ztscltr. KrvhsiniYti. 51 tlhS-llU, 1941. 79. Phillip*. A. J.: Mnrtalily inaii Cancer of lie Lung in Canada (|9.H-I"55), t'anad. M. A. J. 71:245-24J tSrpt.) 1984. Ml. Saii|-. K.: I'unlier ('mil rilmti.sit to the Kinilgemdogical Diagnosis uf Aslicstosis, Ardt. CewerbepatlL u. Gewerbehyg. 9:391-406. 1959. St. Fuiitli. K. \Y.; Pulmonary Oisalslity in Asbestos Workers, A. M. A. Arrlt. Ituhin. Health 12:108-503 I'Attg.) 1955. 85. Sntitli. I- W.: Pncuim*'*iiii.i.ia :,n*l I.nng t'niicvr ttitlt Si-vial Krirmirr- t Sill."..-i- amt Aslv>l<i>is. I'iiin|H-ii*. Mol 5:349 iNm.l l'S49. 85. Smith, W. li.: Survey oi Smte Current Pritisli and European Stmlies oi Occupational Tuntor PnJ'Icnts: Part IIL Aslvsio*. A. M. A. Arch. Imliist. Hyp. 5:245-265 (Marclii 1932. 34. Stoll. R.; Hass. K.. ami Aittrrisf. A.: Aslu-stosis Associated with Hnuiclbteenic Car cinoma. A. M. A. Arch. Ini. Mt-I. 3X :851-8.H i Dec.) 1951. K5. Telebv. I..: (tecuieitimed l.img Cattvv-r, Acta lliHni iuirnwi. o-otre Cancer 3:353-573. 1't.ui; also. Zcutnvll.t Gcwerbcliyg. 27 JJ. |94t). 86. YorwaUL ,V J.; Durban. T. M.. ami Tratt, P. C: Experimental Studies oi Aslicstnsis, A. M. A. Arete lndu*t. llyg. 3:1-43 i.l:ue) 1931. ' 87. Wedler, II. W.: Aslirstosi* and Ltuig Cancer, l)ouiM*hc turd. Wcliiwlir. i/i:575-576 l Aug. (i) 1943. 88. Wegelius, C: Cltangcs itt tlte l.ung* in 126 Cases oi Aslicstosis Observed in Kiulaml, Acta railiul 58:139-152, l'M7. 89. Werber, M.: Pitlmtatary AMicatosis Asso ciated with Carcinoma. ZentraDd. Arlicitsmed. a Arbtitsschutz 2:179-180 (Noe.) 1955. 90. Wural W. II.. nut Gti-yoe, S. U.: rultnooary Asheslosis l 'otuplicalcil hy I'ultmaiarj Tula-rcttlosis, Laiwel 5:954-956 (Oct. 31) 1931. 91. Wyers, H.: Asbestosis, Postgrad. MnL 25: 631-638 (Dei.) 1949. ' ' 95. Wj-ndcr. E. L, ami Gniliani. E. A.: Ktiulouic Factors in Emndiingcnic Carcittntna with S|*vial KrCereitrc In Industrial .lr.*|s*um| Kciiort <( 857 Proved Cases, A. XL A. Aceh. Indust. llyg. 4:521-235 (Sept.) 1951. 653 f,.vaj^)aAP2^iP4iAci47|wi)^ii'. --gy w .. . l'fTir,eeiy i 3 i Civil Action File No: ' CV478-319 CV479-269 CV479-272 CV479-275 U. S. DISTRICT COURT Case No..H.______________ Ex.. Nn. 4^/ Itienl_______________________ vid 5-M SCF-ALLF-01939 ^ 7*? i-s-s* ays ' '  ............................................... AN EPIDEMIOLOGICAL STUDY OF i / LUNG CANCER IN ASBESTOS MINERS v - ..' * * / Daniel C. Braun, M. U. f O f,, wif f.. 7 Medical Director, Industrial Hygleno Foundation / and . T. David Truan:/M. A- ` Statistical Consultant, Industrial Hygiene Foundation Ever since the pronounced increase In the Incidence of lung cancer among males became apparent, there have been atlompts to associate it with one or another of the various elements in the environment of mso. The ap proach used by some workers has been to suspect one or-several substance's and then set about in an Intensive search for lung cancer among persons who <62} have had any exposure to those materials. In this connection, Smith ' writes: "The tendency of authors reporting the coincidental'occurrence o! pri mary lung cancer with silicosis or with any other theoretical ellologic con ditions, has been to emphasise the percentage relationship In extremely small cartes of casos, with control caoco which aro not In any way comparable.-' ll would scein Inevitable that asbestoo ehould coine under scrutiny In this manner, because prolonged exposure to this material Is known to cause a spocific type of pneumoconiosis, and because porsons who show, this form This study was made paisiblo through a grant Irom the Quebec Asbestos Mining Association. - 0250 2. o1 pneumoconiosis otla coma to tatopiy and provide a ready eourca of ma terial (or etudy. It was la this way that report* of the almultaaeou* occur- rooc* at luag cancer and aebastoal* began to accumulate alter the report of a caee by Lynch and Smlth^^ la 1935. VltUa tbe next ten years, about 15 ' (76) additional caee* were reported, and la 195-4 Merewetber reviewed all deaths from esbeetoele recorded In Lag land since March. 1924. - Luag cancar occurred In 1 6% at those cases. Gloyne/*^ whose work Is also frequently .referred to as establishing a connection between asbestoals and cancor of the lung, reported In 1951 that cancer of the lung was present In 14.1% at ashes- ' * 178) tools cases examined by him. In 1941, Nordmann add Sorge claimed to have produced lung cancer In mice which they exposed to asbestos dust. - Since 1951, additional cases of cancer o( the lung coexisting with (56) aobestoels have been reported, and, according to Hueper about 100 such cases had been reportsd up to 1955. As a result, an association between the two diseases appears to have beensccopted by many sulbtrs, and several (89) writers ware using the term "aabcstosls cancer** of the lung. Worker .In 1952, stated categorically that in 7% to 17% of cases of asbestoals, after latent period, of about 1 1/2 to 20 yoar*,' carcinoma becomes established la the lung. ` . . On the other hand, not all authors accepted thla alleged association (80) without ressrvatloa. Seupo In 1939 roported that he had discovered no cases of lung cancer among 620 case* of asbestosle which he had examined; (48) . end In 1942, Hollab aod Aogrlsi expressed tho opinion that th* number 0251 s. of cue* of 4ibaitoili with lung concur was too small for statistical cvtlui* ' (ion. In 1117, YfegsUus^*^ reported 12b radlologlcally diagnosed cases of asbtstosls among 476 worker* In Finland, and found no cases of lung cancer In this group, Goldblatt and Goldblatt In their section of Merewether'a latest book,^1^ states "Out at no stage In all these Impressive researches was any do* obtalnod which might have offered any support to (he possibility that ' asbestos could act as carcinogen. There Is no reliable criterion by which on* can anticipate carcinogenicity and, as is well known, relatively minute changes In the structure of chemical carcinogen nr# sufficient to diminish or effmfnate carcinogenic action. !* ~ If asbestos' la Indeed to bo regarded as a carcinogen, the need is , felt to demonstrate tome property which can be regarded as something more than Inortness." - . These authors advance the theory that, until some more experimental d -7' evidence of direct carcinogenesis by asbestos or a decomposition produce'of (t can be obtained, asbestos might be considered a* * "co-carclnogen" which oaly Induces a fu r tho r development of a preneoplastlc condition brought about by something Independent of tho asbestos, such as an endogenous factor. . Thus lha literature, while tending to support tho thasls that aebeeto* els Is la some way rotated to the development of lung cancer, is by no moans unanimous. Altogether, It Is perhaps mors confusing than enlightening, A careful review ehowe that the majority of tho roporte aro clinical and not epidemiological. They lack many elements neceosery for tho sppllcatlon of 0252 ft jc-*. .*%* T : ., ...................................................... '................................................................................. 4. epidemiological technique tjo their content and.moat.of the authors do not ............... msko claim to having done eo. Whet ku happened Id that euceeedlng author* have draws conclusions and generalised beyond the scope of the works which they quote. Nowhere, for example, have we found references to a population of asbestos workers, although several authors who have quoted the obsarved ' Incidence of lung cancer in autopsies of persons who alno had aabestosls imply that this Incidence applies to asbestos workors, generally. We have likewise been unable to find any study which actually calculated the Incidence of lung cancer among a population of persons who had asbostosls, and not just those who came to autopsy. With the exception of a paper by"Doll none of those reviewed gave any data on exposure and dust concentrations, and even Doll's paper merely mentions "scheduled" areas, by which Is meant, "those areas where procosees are carried on which ware echedulod under, the Ashes. toe Industry Regulations of 1931 as being dusty." . - . Thera Is. furthermore, a complete lack of definition of terms as used la the published literature. For example, the term "aeboatesls", ae used, may refer to changes observable only by microscopic examination.of the lung tlasuo, or It may mean a rsdlologlcally detectablo condition. - Jdoal of the published rsports obviously Included women among their . caeea, bat some of them do not glva the number or proportion of women In volved In the'etudy. There Is also a lack of uniformity ea to what type of exposure most studies have dealt with. Of 99 caess enumerated by Hucpor^^ In J955, only 0253 5. ' tin appear to have originated In the United Stale*, and eevcn In Canada, Soir,.e_ cl the earlier reporta apparently Included aabealoa mlncra, but U can be '* iiiumed, alnce 82 of the 99 caaaa had originated In England, and ibee no aabealoa mining operatlona are carried on la that country, that moat of the reported caiea have Involved worker* In the toxtllo or fabricating Industries. Such factori aa amoklng bablta. family hlatory of cancer, length of time In the Industry, and ago of the Individual case aro also notably absent In the majority of. these reports. - ' ' ` ' With this understanding of the llmijulon* of the eclating literature l* vrtth recpect to epidemiological generalisation, U may be of value to conalder In aomowbat more detail some representative earlier publications, a few of which ware referred to briefly above. One of tho moat detailed etudles and one which deserves the moat - ssrlouo consideration la that reported by Doll^*^ in 1955. This study review* . causes of death amoag aabealoa workers baaod on Coroners' records. It also attempt* to animate the rlek by studying records of men who worked for at laaat 20 years In exposed situations. Doll concluded that lung cancer was specific Industrial hasard of certain asbestos workors snd thst. after 20 years of sapoaura, the risk la ton times aa groat as for tho general popu lation. This article la Important for several ronion*. In addition to tho daflnila conclusion* at which It arrive*. Far axample. It begin* by dating that "In view of the tnfreauoncy of sebettoat*, this targe oumbar of case* 0254 ,... ........................................ .. ' .............................................................. *. * . . ( (61 ciaci of.lung cancer) suggests--but doe* not prove--that lung caucor . I* an occupational hazard ol asbestos worker*." Neither thl* article or any .< prevloo* one which we have examined preaent* any figure* to prove that as- bestosls (* an Infrequent occurrence. Estimate* of the number of perton* potentially exposed to asbestos dust la the United States alone vary from ' 10,000 to 35,000 and the Incidence of asbestoal* of any degree might be higher , than Doll Imagines. . . ,.i This study, like so many others. Involve* autopsy records. The number of persona Involved In the statistical analysts Is only 113 representing w only 1,042.25 man years of life. It Is. also true that Q> selecting men who had J been employed for at least 20 years, the study automatically excluded those who died from other causes after shorter employment. - ' Another reason why this publication 1* of Importance Is a statement * ' ' which It contains to the effect that "the strongest evidence that U (lung cancer) . may he a hasard (In asbestos workers) has been produced by Merewothor and by Oloyna. " '. ' In 1951 Cloyae presented a review of 1205 autopsies on persons ' who had worked in various dusty occupations. This number Included 132 ' asbestos workers, of whom 121 showed "pneumoconiosis*'--presumably a a - ' haetosl*. Primary cancer of the lung occurrod IT times In this group, on Incidence rate of 14. 1% for lung cancer among outowsled asbeatoals cases. There were In hie series 796 cases with silicosis, and 6.9% of the** also showed primary cancer of the lung. The Incidence of lung cancer In Other 0255 v*. X\--*. . ? .*^i7 "J-" ........ . ............................................................................................................7. terra* o( pneumoconiosis wae~6.77r. end In 109 esses -which proved'not'to have ' any Ijrprt/ pneumoconloele Uvea fl.3%. Gloyne considered "the mortality ' ( the aebestoe workers" to he "disturbing", First of all. U la obvious that the paper doe* not deal with the "mortality of aebcitoa workers", and secondly, U must bo bomo In mind that all of Dr. Glayne's casea were submitted to him for study because the findings were unusual for uncomplicated pneumoconiosis. It can reasonably be assumed that cases. Including those of asbestosla, In which the finding* were not considered unusual were not sent to Sr. Gloyne for examination. As a matter of fact. In the same paragraph in which ho ex* presses concern over the Incidence rate In asbestos!*, Dr. Gloyne himself points out that the-rate for lung cancer based on necropsies at the London Chest Uoepltol was 21.1% whlls the figures of the Registrar-General showed only 2.4%. He thus rocogntzsd that autppsles on a certain selected group of cases wore not representative of the general population.. It would sooro, then, that notwithstanding the valoe of Dr, Gloyno's work. Its Importance as m> index of the prevalence of lung cancer in asbestotlcs has been misinterpreted by aomo wbo bare quoted him. All that U really shows Is tho fact that In a group of 121 caaea, selected for special study primarily because they seemed abnormal by preliminary examination, 17, or 14.17> had lung cancer. Morowolher In 1947, In the report of'tho Chief Inspector of ' Factories, reviewed all cases reported between 1924 and 1946 In which as- bsatoela wao tho caaio of death or a coexisting condition. This work wo# later extended to Include all such caseo rcporlod up to December, 1954, by 0256 a which time there were 144 death* Including 205 mates and 139 females. 7 Among them were 55 cases (16%) of cancer of tbo lung, 41 In mates and 14 In females. It Is quite possible that a largo number of as be* totlcs who did not die of their asbestosto, or In whose death certificate It was not mentioned, map have be on missed. The Import of this 167* Is enhanced by the simul taneous statement that tlio Incldonco of lung cancer In autopsies of the general population is only t. The danger af attempting to compare a rate found In 344 cases with the rate for the general population without respect to age, occupation, and many other variables, auch as smoking habits. Is obvious. Lynch ^^wbo with Smith had roportod-the first case In 1935, - reported four cases of carcinoma of the lung in a series of 49 autopsies on workers In an asbestos manufacturing plant who wore shown to have "demon- etrable deposits of asbestos la the lungs." This, of course, is not neces sarily Identical with the disease asbestosle. Lynch, himself, points out that, although this Is an Incidence of 8.2)1, "both flguree are too email for very serious statistical types of calculation." Nevertheless, later writers have used this paper to strengthen the case for an association of carcinoma of the lung with esbestoels. It Is also of Internet that Klutz found only the same number of caeee of lung cancer In a series nearly 10 tlrnee as Urge, L a., four In 478 casos of aabestonle. Behrens, ne quoted In Merewether estimated that, of 309.cases of asbettosls In the lltorature. 44 sbowod associated cancer of tho lung--giving an incidence of 14.2%. This Is an Illustration of generalizing co incidence 0257 obtained in . group of .cades which xveru undoubtedly reported only because-- some of them showed lung cancer, to possibly hundreds of asbestotlcs whose esses were nevor reported. The same applies to the conclusion of Tcle!:)^*'^ who appears to have reviewed reports of 39 autopsies on persons with asbos- tosls among which els cases of lung cancer occurred, Information from sources such as these does not Justify generalisations with regard to mortality rates. .. . Perhaps no one has written to oatonslvely on the subject as has llueper^52 In 1955 be reviewed tho casee^55^ reported prior to that dato and enumerated a total of _' ` (2a Eleven of those were those discussed by Doll und may have booh cases covered by othar authors, Eight wore discovered " (62) by Kcnnaway and Xcnaaway In an analysis of death certificates and. un less Merr.wether's study was incomplete, those cases should have been in cluded in his. report. Of the remaining 80. U U qullo possible that tho 31 contributed by blorowcthei and tho 17 by Cloyno contain iomg duplication with each other or with those of other English authors. -. Principles of the Epidemiological Method Doro<J0> has pointed out that much of what to now though: to bo per- tlnont concerning tho comparative frequency of lung cancor la different popu lation groups has bocn davuloped.from tho analysts of clinical material, par ticularly surgical and autopsy recordo, aupplomcntoJ to some extent by the reported impression* of various clinicians based upon lltcir personal obser vations. More recently, howovor, attention has turned to the systematic 0258 JO. Investigation of this problem by the hoi methods that have proved ao sue- cseeful previously la (be study of communicable dlaeaeea, that la to aay, by epidemiological metboda. In order to apply Ibis method oX Investigation to the problem under discussion, we were at the opinion that, a study should be planned so as to prevldst ' - . I. A well-defined population group. 2. Available data lor all members of this pop- . ulatlon. Including tbo healthy as wall as this UC . '. 3. A sample which is truly representative, of the population. - ' 4. Reliable and valid observations relating to the problem of tbs study. . .. . ' A serious defect, common to most of tbo studies which have been reported. Is that Utile or oo Information concerning the healthy people In the broup seems to have been available to the author. In order to draw a generalisation regarding all asbestos workers, U la noceesary for a study to Include living persona as well as the doad. Limiting the Investigation to tutopaled cases, at has been froqucntty done la earlier studies, still further restricts Us use la gonerallsetlon. Tbo problem with which we ere concerned It whether asbestos minors experience moro lung caocor than docs the general population. The snower oocoioltatoe tho collection o( Tollable Information on ssbettoe miners at a group, as wU as on tho general population. 0259 11 Jl* -.111 iai * It am* advisable to discus* the dlfforcoces between (he epldomlo> logical approach and that used la tho studio* which have been roported to dsts. A very important consideration Is tho /act that lung cancer, la spits of Its Increasing numbers. Is still dlsoase of low Incidence; that Is, In a (Wen population not many person* will contract this particular disease. This /act requires that large samples or group* must bo studied to provide moaalag/ul results. ' . Recognising tho difficulty of obtaining such largo samples, most earlier writers deviated from the epidemiological motbod and sought to clr- cumvoat the requirement of observing well parsons by? 1. Comparing the relative frequency of cancer la various site*. : * 2. Comparing the relative frequency of cancer In . a group of hospitalised patients. '' S. Comparing tho relative frequency of cancer In a group of cases coming to autopsy,' Attempting to compare two population groups, looking only at the ' relative frequency of cancor In various body sltos, may result la.finding a higher percentage (relative frequency) la one of the groups, when, la fact, - the mortality rato of cancer of a particular organ U exactly the same la both groups. This It very clearly demonstrated In tho excellent article by Dorn^^ The mortality rote from a particular cause ts the truo measure of comparl* toa. ' * 0260  u. u. ' " It la apparent tkat aeUcted groups such aa hoapitalUe^ pallenia or M wlepijf1smii may not bo In any way representative of a larger group, and that la dealing with such samples, tbe observer may easily find more cases t\ of a given dlscaoo than would be found in another group of the same also, but representative of-the general population. It Is true that Investigation of iT cases from auch a sample can furnish Information valuable lor research, t: but the uso of this Information In drawing generalisations Is necosearlly re stricted. It la the obligation of both the Investigator and of those who read bis report to make proper comparisons and to draw only those conclusions which are valid and Justified. A good statistical study of cases of cancer of the lung occurring In a group of autopsies can lead to a proper Inference .concerning the frequency of lung cancer among cases coming to autopsy, hut only to such cases. For Information from such n study to bo projected to some larger group. U la aeeeaaary that the autopelee represent a good sample of that larger group. To assume that such Is ths case la nay particular series Is dangerous and Uksly to be false. ' There Is some danger that ths figures reported by soma authors t may bo misconstrued as applying to asbestos workers or even asbestos miners, .5 when. In fact, the authors In question do not make this generalisation, nor I can the generalisation be made for the reasons stated. Close etudy of Che reports revoals that tho percentages quoted relate ouly CO the group of autopsies covered by tbe particular lavattlgatlon. 0261 / | fld>is^~ii in y--w^vr.lS* .11 t y -id ' The preacnt study,. In contrast to tho earlier, works, has-been plan- ssd to utilize the epidemiological method. A woll-doflnod group oi aebestoa miner* he* bees eatabllsbed In euch a wap that It cooetltutea a good cample el the whole population of aabeetos minora la Quebec. Data lor all member* el thia group have been collected and analysed. Thoae concerning lung can* cer have received moot careful conalderatlon. Details o1 the methods em ployed will be set forth later, but the type of approach is considered to per mit of lair comparisons and valid generalizations. ' * ' '' Collection and Analyals of Data ~ '' -cj A preliminary survey of potential sources of Information In Febru a ary of 1956 involved discussions with the pbyolclana In charge of the asbestos companies1 programs and with clinicians, pathologists, representatives of City and Provincial hoalth departments and of the Canadian Cancer Socloty, J: and other Interested persons. It was found that morbidity data, although some .. v *" * ; . what limited, were available fromcuch sources as tho hospitals la Montreal end (Quebec City, and the 13 Cancer Dotectlon Centers In the Province. How ever, beesuse of tho high mortality la lung cancer, it seemed advisable to- depend upon data relating to deaths. These wo found to bo obtainable at tho a . vital statistics department of the Ministry of Health In Quebec City. From the preliminary survey. It was apparent that oKtooslvo and dolalled Information could be gathered with respoct to both the persons employed In the. asbestos mining industry sad mortality figures Xor-tho general population. 0262 'M* ` TrffrjViiiS1aCSii 1**1 70;.; 1u a** .a *n Following this-exploratory survey, the Ihitlaleffort wae directed to the collection of data relating to all workere who had been processed through the clinic at Thetford Mince since lie Inception la 1)17, and similar Informa tics regarding all workere at Aebcetoe, P.Q. Data from-the clinical records included the age, family and personal medical hlatorloa, smoking habits, number of years of exposure, an cellmate of weighted exposure, and the course of the individual's health status or the cause of hie death. From this Information it was possible to formulate a "cohort" which could be well defined, should be representative of thg whole group, and could be followed for a deflnlto period of time. All of the available experience Indl- ' ca'les that the development of aebostosls in loss than flvo years of oxposure must bo somewhat rare. Accordingly, the cohort was defined as Including srsrjr wiser who had a total exposure of five or more years, and who was on Off'ee-tr*t* //* ths employment rolls In DSO.^Thli cohort was then followed by means of tp h*Vl/4'/slt7^ a/bfC */*' /yoto/r/- . the aaaunl physical'examination records through a alx-year Interval, 1950 . . . through 1955. All data regarding this group were then tabulated In order to determine the characteristics of the cohort. For those who survived the en tire period, reference was made to the physical examination results and x-ray findings st the end of the period. Those who hod dlod wore tabulated separately sad tho cause of doath corroboralod by examination of the death certificates. A iurthor search was made concerning those In the. original cohort who re mained unaccounted for when the living and the known dead had been tabulated. They represent moo who had left employment through retirement or resigna tion. Eventually, all but a small number 0/ Ihoee were accounted for as either .... ^ - r.'<- , -..r^T^.s * < ' .. . .-. -*_ IS. living or dead, and In (he latter event, Lk ecu n c of deeth yea substantiated |a a altnllar manner, and the results added to the original list ol deaths. Death certificate* lor the Province ol Quebec lor tho years 1952 |a. 1955, inclusive, war* reviewed In the department el vital statistics ol the Provincial Health Ministry, together with statistical summaries ol the causes el deaths In tha Province by counties. All cases In which death was certified is having been due to primary cancer ol tho lung were examined lor such In formation as place o1 rsaldenco, occupation, date of death, hospital In which dsath occurred, and whether or not an autopsy was performed. Cases la . 1* .n ehlch lung cancer was given as a cause ol doath, but In which it was not specified as to whether tha cancer originated In the lung, were also reviewed to an effort to Include all instances of primary carcinoma of the lung In tho > study. The statistics for the Province of Quebec relate to population, total deatha immmn aad deaths from lung cancer. Those were collected nS and tabulated by counties and by sax for tha yeara 1950 to 1955, Inclusive, from them, doath rates for tha general population ol Quebec and of individual counties were calculated for epoclflc year* aad aaalysod by cauee. i. Practically all employees of ooe company are covered by a group policy of life Insurance which, fortunately, nearly all ol them contlnuo to -. carry when they retire. A vary low are not covered by this policy, and Iboso who leave the industry lor one reason or another excapt rullrsmant usually art no longer covered, but this Is likewise a smell number. As an additional coco .'.ww `i- ~1^7 15. living or dead, and In the Utter event, the caueo of death was eubatanllated Is a ilmllar manner, and the results added to tho original liet of deaths. Death certUlcatea for the Hrovineo of Queboc for tho years 1952 to 1VSS, Inclusive, were reviewed In the department of vital statistics of the Provincial Health Ministry, together with statistical summaries of the causes of deaths in tho Province by counties. All cases in which death was certified ss having been duo to primary cancer of the lung were examined for such in formation as place of residence, occupation, date of doath, hospital in which death occurred, and whether or not an autopsy wae performed. Cases in .0 which lung cancer was given as a cause of death, but In which It was net epoclfied us to whethor the cancer orlglnatod in tho lung, wero also reviewed la an effort to includo all instances of primary carcinoma of tho lung in the liudy. ` - ` r The slatla tics for tho Province of Quebec relate to population, total ii: deaths - < 4. .( , rm **< l* * <.. Aug doaths from lung cancer. These were collected (li aad tabulated by counties and by sex fer the yoare 1950 to 1955, Inclusive, t-i from them, death rates for the general population of Quebec and of individual l. counties were calculated for specific years and analyzed fay cause, ' Practically all employees of one company are covered by group policy .of life Insurunce which, fortunaloly, nearly all of them contlnuo to csrry when they retire. A very few are not covered by this policy, and thoto who leavo the Industry for one reaeou or anothor except rellremont usually arc no longer covered, but this Is llVowloo a email number. As an additional 0265 16. check upon the Information obtained from the clinical record* of/thl* group, the record* of the life Insurance company ware eumlned for all death claim* paid under tho policy, and particular notice wae taken of the claim* in which th* proof of death waa baaed on cancer of the long. . Death* from lung eancor among aabesto* miners were thus deter mined from tha clinical record* in the medical service of the Industry and checked by mean* of tha death certificate* and laeuranco company record*. Th* deaths were then verified Individually by reviewing them with the physicians b> charge of the medical services. In this manner, there was established a Ust of cases In which primary cancor of the lung 1* considered to have been provod as the cause of death. A few casas In which lung cancer la strongly suspected but not proved a* the cause of death woro considered separately. Uortallty ratee have been calculated using both tho "proved" and the total of "provod" and "suspected" cases during the years under observation. Com parison* ware then made botwoon tho death rata* from the same cauee among ' specific segment* of uaexposcd person*. All lung cancor deaths, both suo- pseted and proved, were carefully analysed to dotormlne posetble relation ship or correlations botwocn th* devoloproont of lung cancer and any factor known from the clinical record* such a* family history of cancor. personal history of heavy smoking, coexlotenco of aebostosl*, or exposure to asbestos. In addition to this analysis of deaths occurring In tho cohort and during tho yaaro under observation, every known death from cancer of the lung, as well se every case dtsgnoeed but ollll living, has been.tabulated and 0266 A. 17. inslyasd... They will he discussed separately from thoae Included In the - population end time-interval under etudy, A comparison ol lung cancer mortality In Uto asbcatoe-producing countlee has been made with that in counties which are far removed from the aebestoe mlnoe and In which, proaumahly, no aabeatoa minora live. Finally, la order, to broaden the comparison of death rates la dif ferent population groups, the rates have bcoa collected for Canada generally, ted for the United States, according to the most recent published and unpub- Uibed material.' . _l ` ;~ . Rosulto and Interoretatlon The cohort which.was constructed according to the criteria described b the procedtag section has been considered Individually and compared with Ihe general population. Description of the cohort will be presented here as a preface to the results of the etudy. ' .. ' Original Cohort - Lest Parsons Deducted Final Cohort - ' Living in 1955 (working and retired) Dead by 1955 ' Cancer of lung Questionable concur oflung Other causes Unknown cauaos Smokers Nonsmoke.rs Unknown . . 6091 ' 13} 59S8 5771 lb7 9 3 109 6' 4073 1105 20 0267 18 Tabic* li 2, 3, and 4 praaopt age, number of'years of employment, weighted average exposure, and emoklag hablta of the cohort. . A comparison of tha espoaura to aabesloe dust la proaonted In Table 3. /M<e-*-* (LK**r - All were placed In ona of throe categorlaa. reproaantlng Increasing degree* of exposure baaed on a weighted average of the years spent at various levels of dustiness. The degree of dustiness for each job category was deter- wined after conoultatlon with person* familiar with th* environment and con ditions In the various work areas. For the purposes of calculation..the as sumption has been made that the relationship between these- categories is linear, and that category II Is twice a* dusty, and caletory 111 three times as dusty as category- i. ' The fourth variable, amoklng habits, was similarly tabulated and Is shown in Table 4, This was Included bocauee tho Information was available ' sad because emcklag was regarded ae one of the variables which, besides the environment, could conceivably influcnco tho development of lung cancer. As oasd la this prsssntatlon, the term smoker refers to a cigarette smokor, habit ually smoking more than flvo cigarettes per day. Persons who smoke pipes or cigars exclusively were not considered to be smokers for tho purpose of hit study. . 0268 W'k1^ * "*''**7 i ' ' * f ' i? i,f f'W-'SfVS %* ^JT " ' v -c-^" \ -- --. ..av*.v.j.< *>'",'^v.r i?. ^^tj * tablx i ' Numbor and PerCooUga Distribution by Age -* - r-r' tbsr -! s Age ai-j .. o i!vt! :,A Lt'ZI :l >U tfrUlly ' 20-44 . 45-54 55-64 65 4 ' Unknown Total* Avrage Ago loJi'j.*' * * Loos than . SJl Number " 3901 1124 615 315 3 ' 5958 - :i 41 . t Per Coot 66 . 19 10 5 loo?* V:* *r ' TABLE 2 .w. .<* . Number and Percentage Distribution by Length of Employment fit#** 11*.. iilml.in- - Length of . . . ' Emoloyment Number . ' ni ^fcai. .' 5-9 1795 lit ).'*.. 10-19 . 2398 20-29 922 #' JO-39 40-49 . 603 - 185 ' i a i: 50 55 Totale Average Year* of ' 5958 Enployinent 18 fpooa ftim*wfl-g . ' Per Cent .. ' 30 40 16 10 3 1 1007* . 0269 S-. ' / >iw'TiraiVi ^Yj ----' p'- :^*rtiWJu _ .- __ TABLE 3 .. _ Number end Percentage Distribution by Exposure Category Cxposura Cetegory I n m Unknown ' . Totels Average Exposure t Lses 5 f. . Number 2031 2150 1772 5 5953 2,0 Per Cent . . .. ` ' . . * 34 35 30 100% , .. . r TABLE 4 Number end Percentage Distribution by Smoking Hsblte Smoking H&blts . Smoko rs flonemokers Unknown Totals Lets then .5% ' \ Number 4673 1265 20 5956 ' . '. ' Per Cent 79 21 Too* 0T7V 01 21. " Table 3 present* the year-by-yor oxpertencp of the cohort tad Indicate* the aumbsr of death* each year from specified cause*. In general, a caee eras considered to be'proved" as os* of primary cancer of the lung erhes the records showed that the diagnosis had boon supported by an autopsy 1 n <u undo w r Itt/. er surgical resection of the long with microscopic examination of the removed tissue. In one case so considered, however, diagnosis was confirmed by bronchoscopy with visualisation and biopsy. - la aaothor, although there was no autopsy, the diagnosis of primary cancer of the lung seams to have boon r-l V beyoad question. < : . i: O ' TABLE S Yeor-by-Yeor Experience of Cohort end Death Rates per 100,000 Man-.Years of Risk Tear No. Alive At Beginning of Year Provad . Primary Ca. of Luaq C aue o of Death duopoctcd Primary Other Ca. ofLonq - Caueea Unknown MssYears of Risk 1950' 5958 1951 5942 1952 5922 1953 3885 1954 5848 1955 5810 Totala ' ' 1 ' . : <'2 l. 12 1 5950 .2 . . o - ' 17 . - - 1 5932 0 . 0 - 37 - 0 5903.5 2 .1 . 34 0 5860.5 1 0 33 4 5829 3 0 30 0 ST>0.5 T9 3 . nr 35271.5 "Proved" rate por 100.000 man-years of rlek 9 . 35271.5 25,5 "Total" rat* por 100, 000 maa-yearo of rlek j^^ 1 * 3d, 0 . 0271 i -* frV t*~*`; ~r_ V * !?Vi r'Tr -A:-' * V,-L The term "luajiocted" primary cancer of the long wn applied to O 41 thole caaca la which the dlogaoal* remain* la doubt but eomc of the evidence point* to cancer of the lung. There wore three auch caaea. The term "man-year* of rlek" ha* been uaed to mean the number of 16 man al rlakfor the year under obaorvatlon. An individual who lived through* efl out the year wa* counted aa a full man-year of rlek, but one who died during lid the year waa counted a* one-half a man-year. VC i-jj Deathe occurring In the cohort, and-In which lung cancer la conaldered = pjJLXa 4 _ to have been proved a* a cauee, are ahown In tabgloteifcfgr tvle*. Alao ahown art three daatha which have been considered aa "auapoctedM lung cancer caaaa. ' -fAVl "Proved" Caaos of Primary Cancor of the Lung or v Name i. A. J. i. N. P. 3. R. M. 4. c. a. 5. A, S. 6. w. r. 7. u 0. 8. E. U 1. A. R. Ago Gmokor Expoaura Died Autonay Aebestoala 66 Toa 16 yra.tn Cat, 11 10-12-51 Yea Yea 65 Yea 34 yra. la Cat, I 5- 3-55 T No 65. Too 37 yra. la Cat. I 7-20-55* No No 59 Yea 32 yra,In Cal. I 8-20-50 Yoa . No 48 Yoa 22 yra, la Cat.ll. -51 Yoa Yea 61 Yea '33 yra. In Cat. Ill 4-30-53 Yoa Y* 56 Yoa 30 yra. In Cat. 11 11-22-53 Yoa Yea 37 Yoo 16 yra. In Cat, 1 d- 5-54 Yoa . No 68 Yot 28 vra. In Cat.Ill 5- -55 Droncb. No 7 A 4'/i? 'J ' "Suapectod" Primary Cancor of the Lung Nemo 1. J. T. 1. R. D. 3. P. P. Ago Smoker r.xoonure Died Autopay 49 Yea 32 yra. In Cat.UI 10-25-50 No . 46 Yo 33 yr*.In Cat. Ill 7- -S3 Ye* 65 Yo* 42 yra.tn Cat. U 9-30-55 Wa Aabc*tool* No Ye* .No 0272 ii " Ait Indication of tho Importance of these "suspected" cim la Interpreting the results of the calculation* la desirable before further discussion of the mortality ratea which are derived la later tablea. For example. It happoaa that tho rate found for the proved cases Is cloao to the "expected" rate baeed oh .the general population figures for the Province as will be shown later, and on which baste, we should find olght deaths from lung cancer among the cohort. Actually, nine cases were observed. If, however, . . * .* the three additional "suspected1' cnees are Included, Increasing this figure to 12, the total would be very close to the 95% level of signif icance. Howevor, having found just 12 cases, we are not above this TTiCVfd<W '. level, and film mil jwecttts^fh .LJLJtOg tho hypothesis that asbestos minors do not have a higher mortality from lung cancer than does C/W-r- a <<**/ the general population Nevertheless, the occurrence of 12 cases la this sample would Increase the rate to a point which app roaches the significant level. Because of the tremendous Importance of the questionable cases la this respect, eomo detail :rogardlng them will be given here. 24. In one of these esses, the suspicion of esneer of tho lung Is based upon the x-ray Interpretation and, although no autopsy was performed^ the death certificate Indicates that death was due to lung cancer, it Is well known that the x-ray appearance of fibrosis, especially If a localised density or a superimposed tuberculous lesion Is present, can simulate that of a tumor, and by ItseU, doss not justify the Inclusion of this caso as one of ''proved" cancer of the lung. A second case was certified as having died by reason of hydrothorax, possibly due to lung cancer, but again there was no surgery and no post-mortem examination, In the third case, although it was subjected to autopsy, two pathologists disagreed as to whether lung cancer was present. The death wao certified as having been due to chronic myocarditis with neph ritic and pulmonary congestion, and possibly cancer of the lung. Oa the basis of these facts, it seems unwarranted to Include these three cases among "provod" instances of lung cancer. On the other hand, they, cannot. In falr- etsa. be disregarded completely, U is for this reason that mortality rates here bean calculated both way a. g . Table/? gives the rate# by age groups. " '* ' itfiiergstf ihm- TADLE 6 Numbor of Parsons ud Number of Lung Caseor Dottbi by Ago Croups Axs Croup - Porsoss Luir.Caaccr Deaths Proved Total -S* ; n. 20-44 45-54 55-64 654 Unknown Total* 3901 . 11 1124 13 615 3 3 . 315 4 5 .3 . .0 0 3953 '' 9 12 'J u/i* '``V ilh > lo :ieo j4 ` * ,Z. Annual Lung Cancer Death Rato a per 100,000 - Man-Years of Exposure by Age Croups Ape Croup 20.44 45-54 55-64 65t Unknown VotoC*' tf.V * -J . Proved . ` 4 *' ' ' 15 81 212 . 0 *7T * .V .. * - . Total' .4 44 81 265 0 34 . Tbs rales by length of employment era shown Is Tabto During lbs first 40 years of employment, tho r&to rises, ns obeorvatlon which seems fltatlbU clnco tbe men were growing oldor. Howovor, iltor 40 year* of ex* posurc tbers are so `'proved*' cases reported for a total of 240 tnon during (he lU ytn, oribout 1440 aaa*yeAri of exposure. Wbon tho "auopectod" 0275 ^-^rtii-*******-* * '' cases are eddsd, ono caao dope show .up In (hi* porlod.- This would produce ' rite el 69 per 100, OOO.agaUt demonstrating the Importance ol those question able, but uaprovod, cases to tho Itnal conclusion, because, 11 there were so (Mil In th!( ounobor el mas with long exposuro, and U asbestos lo a carclno- genic agent, It must be concluded that those 240 men have demonstrated con- Iderable resistance, Thla^a biological phenomenon which has been observed prsvtously and Is consistent with tho theory ol an intrinsic or endogenous lector la cancer. The only other explanation would be that the susceptible members -- ' ' ' : IS . ol this ago group bad died earlier ol lung cancer. Tablo ^ which appears * ** *" * '*** `' * latsr la thl* section Indicates that the membora ol tho cohort did not die Irotn lung cancer at a younger age than the general population. . TABLE f Number ol Person* and Number ol Lung Cancer Deaths by Length ol Employment ' ' Lcscth ai Employment Persons Luna Cancer Deaths " ' Proved Total , -- l- 10.19 20.29 3009 40-49 50* Totals '. 1795 - 2398 . 922 603 185 . 55 ?95? ' ' ' 0 0 - 1 . - _ 1 *' 3 3 S' . ... 0 7 .r i 00 .9 12 . Annual Lung Cane or Death Ratos par 100,000 MiaYc&ro of Exsooure by l.nn<*th of Employment Ut'.tli ol Employment Proved - 5-9 10-19 . 20-29 30-39 * 40-49 50* Over-all 0 7 54 138 0 0 25 Total 0 7 54 193 90 0 34 C~76 1 .. ; J V/--7 / *Vi8 r*T--'W^nSi 27. . it <C % The rates by weighted exposure arc shown la Tabic and U will be . *4 * Bitted that thty present strong evidence against asbestos being a carcinogenic agent, for. If exposure to asbestos la la aay way connected to lung cancer, we IwC :* 13 *-: .9 Aj would expect that tbe longer and heavier the oxposure, the higher the rate that would bo found. Thejraly possible error la this Interpretation could occur If the weighted exposures were. Inversely related to years of employment, In which case the heaviest weighted oxposure (category 111) would show the short est length of employment. Table which lists the number of pereons In ` 'V4*i *--$ 4 various exposure categories by length of employment ladlcaleo that this error has aot occurred. In fact, the average number of years of employment for each exposure-category Is almost Identical. .' ' Expnsuro Catetory 1 U 111 Uefcaetra Totals ...................... ... TABLE if fO Numbor of Persons end Number of Lung Cancer Deaths by Exposure Category Persons 2031 2150 1772 5 5753 - Lung Cencer Deaths Proved Total 4 .4 34 24 00 7 12 If (Table 9 continued on aoxt page.) 0277 TABLE / (continued) Aanunl Lung Cineor Denth Roto a per 100, 000 Mm-Towi o< Exposure by Exposure Category V** JCxpoion CMe^ory . ,,J a y ' s a m Unknown Over-all Proved 33 23 19 0 25 4 Total 33 31 37 0 34 TABLE V| / Number of Peroons in Vnrlouo Weighted Exposure Categories by Length of Employment ' Length ot Employment -- .* sl 5-9 10-19 20.29 J0-J9 40-49 S0 ToUlo Average years of oitpouro Wetnbted Exooeuro Catenorlos 1 U 111 107 663 314 247 * 76 24 2031 598 - 883 363 218 67 21 2150 490 851 243 137 41 10 1772 17.8 17.8 16.6 Unknown '0 1 2 l 1 0 ? 29.0 Tout 1795 2398 922 603 165 55 5958 17.5 0278 . .sv -iUrft'.gv-'WfiW* "STflerKt . Table yi. which develop# the rata* (or smokers ud non-smokers, ( roost striking. It shows that not single csss of lung cancer developed among the 1265 nonomokers and that all cases o( lung cancer, both "proved" and "suspected", occurred la smokers. .' Table 10 eras so striking that It was (elt that (urthsr verification eras necessary. It was possible that some abnormal distribution may have . occurred, e. g.. tbo noaomokore may have Included a larger percentage of o i- tr young men. Consequently, a4dlttonal Tablos, H. 2^, and & wera constructed te show the distribution of smokers and aonsmokers by age, -length of on. ploytnent, end degree of oaposure. Although there are slight differences, they do not account for the fact that all observed cases, of lung cancer were ' [3 . In smokers. In rospect to age (Table Tfj the combined avarage ago of the . idsmokers was d. 9 years less than that of tho noasmokers. Table K shows a that aa far as length of employment le coacorned, the smokers had worked if-. I shout 2.3 yeere lose on the. average than tho noasmokers. With longtr ox- pssurs and greater age, one would expect that nonsmoking group j to show ' if s hither rate If lung cancer ware due to asbestos. Table yi shows that the average exposure category wae almost the tame for tho two groups. There fore, this vartebls seems to bs of no Importance In accounting for this difference, - . The result of this additional uulyili Is that none ef these factors 13~ appears lo lessen (be effect of Table 14- -' 02T79 . T/.BI.2 ro- 10, : Numbtr of Pereoi a and Number of Lung Cancer Dealha by Smoking Habit* *GC *v *#vi l-C-i Smoker* Nonamoke r* Unknown ' Teul* * c: Persons Lung Cancer Death* Proved Totai 4673 1265 20 5958 . - 9 0 0' 9 12 0 0 12 _T h . `to Anna*! Lung Cuicer Death Roto* p*r 100, 000 Men Year* of : .^otare * * by Smoking Habits . :<J - i\C Proved Total Ui* I 40* iS Smoker . Nonamoker* Unknown Orer-ali - - d 4 32 0 0 25 43 0 0 34 . a <ol nii 1 0280 ................................... '........... >. \3 TA01X . Number of Snokiri and Nonamokara by Ago Croupa ` 7 *% A*a Croup uv5 \ori .:i.o 20*44 45-54 55.64 65 4 Unknown Total* Average Age Smoker 5200 896 411 164 2 4671 59.3 Nonsmokor 689 224 202 150 0 1265 44.2 ` . Unknown ** 12 4 2 1 1 ^20 40.7 Percentage Distribution of Smoker a and Nonrrookora by Age Croupa Aga Croup Smoker 20.44 45-54 15.64 65 * Unknown Tout* 68.5 19.2 8.8 5.5 ToojT Lea* than ,05% Nonomokor 54.5 17.7 16.0 11.8 .0 100% ' '' . ' .' Unknown 60.0 20.0 10.0 5..0 5.0 100%' , 0281 \*r TABLE 1L Number of Sraokara and Noaimokin by Length at Employment L' Length of Employment l'.*0 J* I * $-9 10-19 nc1. u rjvl 20-29 30-39 40-49 sot Totab Average Length of Employment *! Smoker 1408 1967 722 433 . ' 110 33 4673 17.0 Nonemokor 377 426 199 166 73 22 1265 19.3 ----------------------- . Unknown 10 4 2 4. 0 0 20 16.0 -- jVO; C Percentage Dletrlbatloa Of Smshors and Nonomokere by Length of Employment :i **-ci to-e* > :i y'4itU * Length of Employment 5-9 10-19 10-29 JO-39 40-49 30 4 Itult Smoker .' 30.1 42.1 13.4' 9.3 2.4 .7 1007, Nonsmokcr- ' 29. B 33.7 . 15.7 13.1 5.9 l.B 100*/. Unknown sO.o 20.0 10.0 20.0 .0 .0 Too?. 0282 1 I* TABLIS Hs NumUr Smpluri ind Nonsiuokers by Sxpoiua Category Erpoiuro Category Smoker I 11 m Unknown Totals Average xpoeuro Category 1551 1691 1425 . 4 4673 2.0 Nonsmoker Unknown 474 452 : 338 - I 1265 1.9 . , ;- '4 7 9 0 20 2.3 ' ' Percentage Distribution of Smokora and Noasmokara by xpoaure Category . Exposure Category 1 U IU Uoknowa ToUU Smoker 33.2 36.2 30.3 0.1 1007. Noncmokor Unknown - . ' 37.5 35.7 . 26.7 - 0.1 1007* 20.0 35.0 45.0 .0 "Too^ 0283 Com pari* oa of. tho Cohort Experience with that of the Provinco at Quebec, Dominion of Canada, and the United State* ' la order to make a comparison of the experience among asbestos minera with that of tho genornl population of tho Provinco of Quobec, sta tlltlei were gathered, as stated earlier. In the offlco of the Division of Demography la the Provincial Ministry of Health. The data on tout deaths, deaths from all forms of cancer, and deaths from cancor of tho lung were Qbtalned'bjr sex and by county for the years 1950 through.1955. In addition, all death certificates which specified primary cancer of tho lung, and all those which Indicated lung cancer but did not specify the origin, were examined for th* years 1952 through 1955. - ' l(r ' '' Table 1^ gives n tabulation of the numbor of deathe from lung cancer la lbs Province and In the cohort for the yoaro 1950 through 1955, and chows the annual rate per 100,000 la these segment*. It will bo noted from the labia that the mortality rato for tho "proved" cases .In tho 'cohort Is only - lightly higher than the rate for the Provtaco, Whon the "suspected" caeca era Included In the calculation, the rate for the cohort rises to 33.8 per 100,000 which li ebout'50% higher than the rate for the Province. This, It will be recalled from the previous dlacuealon at the offect of the "euspocled" caaoe oe the result!, approaches hut does not exceed the elgnlflcant level. 0284 OawVi* 36. */ One further Interesting observation from Teblo l/li the rather marked Increase la the total number of case* for the Province between 1950 and 1955. Jt l* assumed that at least partof this Increase Is di/e to Im proved recognition and reporting of lung cancer during tho Interval. For this reason, tho years. 1954 and 1955 were thought to be more nearly repre- \ tentative of actual coadUloae, Even so. U (s qulto likely that the geoorol ' population la not otudled for lung cancer with the some diligence with which ' gtls disease le looked for la the mlaere, and U sinus probable that the tnor- tallty rates for the Province may bo low. This would appear to be subatao- : titled by the fact that the reporting of cases la the cohort ohowed no such . c; (.. Cl Increase over the same period. ,7 , : . . , > Table io was compiled to show the annual age-epeciflc lung cancer 4 " `* i rata of casao la which the dsath certificate merely read "cancer of tho lung", as distinguished from those In which the diagnosis was confirmed by autopsy, surgery, or biopsy, Tba. term "specified primary"' rofors to those cases In ' '* .. I. t * , . ' `* , S` , . iksse two eategorloe In which (he tumor was specified as having originated . Is the lung. It will be noted that, of the total cases reported In 1955, a much higher percoatage than In 195-4 wero spoclflod as primary, Tho table also ihsws that a higher percentage of the total cases certified In 1955 were proved, sgsla Indicating'Increasing Interest In this disease, - 0286 /7 . TABLE W- *. Age Croup. 2Q-44 45-54 55-6-1 . 65 Totals Lung Caacr Death* (or the Province of Quebec . (D^U from Death Certificate*) Catimated Population Total Certified Total Proved , Specified Primary Total Proved iyrr Tout . Certified Total Proved Specified Primary Total Proved 777,000 202.000 1)7,000 J2I;000 1,2)7,000 ' .: . '/ . 17 67 too in. 195 13 38 33 120 II 43 *9 68 .171 9 29 32 ;.29 99 * 17 ' 9 60 35 i .117 57 148 54 342 ` I5S 17 56 116 . 148 337 9 32 57 54 1S2 * . Eiitmito for poj^ilallon obtained by applying I.9SI percentage* for.age group* for mate*.to the total population for IVSt; a* glna In Aapport,. Dir. de la Demographic. Age Group 20*44 45*54 55*64 65 Over-all Annual Lung Cancer Death ftatoe per 100.000 1954 - ~LZ Total Certified Spacified Primary * ' Total Proved Total Proved 19S 5 Total Certified Total Proved ` Specified Primary Total Proved 2.2 33.2 73.0 91.7 23.8 . 1.7 17. 8 27.7 27.3 9.7 1.4 * 21.3 - 50.4 56.2 IS. 4 1.2 14.4 23.4 24.0 6.0 ' 2.2 29.7 85. 4 122.3 27. 6 1.2 T.l 41.6 44.6 12. S 2.2 27.7 84. 7 122. ) . 27.2 1.2 15.8 41.6 44.6 12. 3 / r* i t il. ya4|>Vt*;i''* *** v ir 4 V* :. ' !=...... 35>. A comparison has been mado btlvooa tho ago-opeclfic raios shown i ' tl .. 1 ' ; la Table Iff, and Ihoss ior the cohort, shown la Table kf. An average of the v ; Hit and 1995 raids for the Province has been used, since the 1955 figure '"P*pacflrt83?x: was higher and may have been exceptional. $ This comparison, summarized In Table Iff^ shows that the observed number of deaths la our sample la not significantly greater than the expected number of deaths, based on the averago of tbs 1954 and 1955 flguroa for the i province. It Is true that. In the caeo of the age group of 55 and over, the ft" deaths provide a figure which Is almost significant at the 9S level. However, It should bo noted that thla number laeludoa one of the euepected . V but unproved cases'provlously referred to. furthermore. It Is rather likely > that the rate for tho general population ie understated In this age group,, for : [ |bt obvious resson that tho exact caueo of death In the very old ts not a matter . si the same Intensity of Interest as It Is In younger porsons. . . .v. . TABUS IS Age Oroup Comparison of the Actual nod ExpecCod Number of lain Cancer Death# by Ano Among Aobetloe Miners Provinco xpoctodT Observed No. Total dpcclilod Primary No. ef ' 1 Hu. -of of Doaths Hate per 100. 000 Minora Deaths - Proved 1 otal 20-44 45r94 19-64 65t tfskaown 1.8 24.5 67.6 89.3 -- 3901 - 0* 11 1124 2 .... l 3 615 2 33 . 315 . 2 3 45 00 S Actually ,4 '' 1 Tbs sspectod number Is baaed on tho average of the 1954 and 1955 tgc>*peclfle ratoo for the Province of Quebec. 02SS . 39. Tabic alio anaccri a.quceclon previously raised. Il showe that ' >-i ihs members of the cohort have Dot died from lung cancor at an age'earlier ' l then the geocral population, and that such an explanation cannot bo offered i v for the absoncc of lung cancer In 240 men with more than 40 years of em ployment referred to on page 26. . vi Before leaving this comparison of the Province with the miners. U .MU should be shown that their age distributions are reasonably the same. That VT this I* the case can he observed from the following tabulation: -<11 7'aolZ' f? .. Age Distribution of Adult Males for the Provlnc# of.Quebec. 1951 -.H (Rapport, 1954) .rtf i 6js iiti Qroup V Provlnco __Jjhimbor_ Porccnte^ Percentage In Cohort 20.44 45-54 55.64 65 4 Total 727,135 10B.952 120.944 113.467 1,158,496 63 A* 66 16 19 11 10 10 5 too Too A. . It thould be resaemborod that ih mlairo retire mnd coa*oguontiy |( c*o b expcctod UiAt th oldtot Ago group wUi bo largor ia the general popu2* It lion. The data preaented In Table Vf Indicates that tho lung cancer rate *\ jtotrally docroasos after ago 70. Thersforo, we could expect the rata for J * til people over 65 to bo (mailer than Uio rato for the group between 65 and 75. srblcb would apply to the oldest group of minors, ft Is folt that by using tho whole adult ir.alo population, we havo developed rates for the general yopu* lotion which ore cv.ucalnt law than li vra Lnd beta all-.- lu c?clcd U pooplo la lha gcssrsl pcpcktlaa over 75. A coaspartsoa between Ibo aabcctoa atsora wd tfci) population at tiu Pomlolca as a ehols ess aiads, calcj O statistical asterlal & boa OJftroi aacrcca cl cos scarce, PtllUpa (77) pis xga aox . upodflc rstos.fcr Ccrr.ria lor three periods botvoea 1)31 sad 1932. P.el03 {or oaalso arc circa (s Toble p. AgeOrtrep t'nlar SO' SO-24 35-39 40-44 45-40 00-54 05-99 60-C4 es-09 70-74 73-73 o-m 23 piss AU RQC3 /St t*.*, TAE&lh ^------ ........ . ____ Orcun of ;ycarp t V.;- <;ji 1051-1953 1041-1243 UBD-1352 0.3 0.9 i < 3.0 3,0 6.3 0.3 * - ' 12.7 13.3 . 19J 10.7 15.0 CJ 11.4 . 2.0 0.S 0.0 c,. y 8.3 6.4 13.0 U.9 ' 7 37.0 83.7 84.5 . 80.0 SO.O Z7.9 14.3 7.1 to 0.6 3.0 0.5 16.7 37.2 63.7 77.8 102.0 56.3 03.0 53.7 71.0 15.D 7 vt--1 ' "* WGrtnlUy Irom bay cocecr la CsantuT'USl Us 1)92* 0290 / 41. - . .. ' " '' These figures show strikingly (ho Iscreaee In raise between 1951 tad 1952, and this Increase Is particularly marked cftor age 50, confirm- . ls| an observation previously made, to the affect that until recently lung cancer has probably been under-diagnosed In the older age groups In.the general population. To use tbooo figures lor purposes ot comparison. It Is necessary tt combine the rates for certain age groups la order to conform to tho ego (Ulrlbutlons ueod In this study. Slues tho oxact populations In osch age-group (or tho years Indicated le not known, this must be an approximation. However, Us rates would be eomewbat as loUowsi - Ago Grouj^ 20-44 45-54 55-54 65 a . . - Rato 5 27 69 90-95 These rales ers, lafgoneral, lower than these developed for tho total (proved and suspected) cases of lung cancer among tho asbestos miners, lbs ouly large difference, however, le In tho age group of 65 years and over, lad It Is quite possible that tha rate for thlo group may have Increased for Canada boiween 1952 and 1954 a* It did for the Provloco of Quebec. (Sec Table J5.) f'j 0291 . -V ' / V r- rtw- c Ml Ill ri 42, A further comparison hat been tna.de with an over-all rats obtained * from the American Cancer Society for respiratory cancar deaths In Canada ri la 1953. This rata, for tnaloa, la 20.8 par 100,000, five more per 100,000 tfcaa Phillips' 1950-1952 rata, and compares with 25.3 par 100,000 for proved cate* and 33,8 par 100, 000 for total caeca among the asbestos minors In this study. It Is therefore obvious that there are aa Important differences between ul the raise for asbestos minors and thoso for the gonoral population of Queboe lb. sad the Dominion of Canada. . .. 1 Since It la probable that figures for the United Stales are more . _\ ' *1 complete and, therefore, possibly more comparable to tha data for the minors, S|s*spscUlc rates wars computed from "Vital Statistics of tho Unload States", Volumes I and U, for 1932. Those rates have been tabulated la Table HT, jy. TADI*E y4 ... ... ' Number of Deaths and Doath Ratos per 100, 000 by Ago Qroupo for tho Adult Mala .Population of - tho United States--Data From '.'Vital Statistics 6f tho United Stales". Volomes I and XI,. 1952 . \ \ / A]* Group 10-44 45-54 * 55-84 85 y Taut Population 24, 544,000 8,063,000 6,340,000 5. 670,000 44,619,000 Casoe 883 2979 6254 6403 16, 599 Rate per 3.6 36.9 98.6 114.3 37.2 0292 4). It U apparent that these ratal compare favorably with those far . :i the ttbaeloe miner* ai ahourn In Table Stll} other.*ratee for the United Stale* were obtained from the American Cancer Society, and for males, tbsea wars 25.3 per 100, 000 ta 195J, and 2B.0 per 100, 000 in 1955. They are oat Identical with the rata calculated from Use figure* of tho office of Vital Statistics, but this Is possibly because the American Cancer Society rales ars for males of all age*. Nevertheless, they, too. compare favor ably with the rates of 25 (or 34 for total cases) obtaining among the asbestos miner*. . '. ` Taming for a moment to a comparison between the aabeato* miner* *ad parson who are exposed to asbeatos In one form or soother (as dis tinguished from the general population groupo Just discus sad. who have no (58) rpesure) an Interesting obeervatlon can be developed by deduction. Huepor gas stated that there are about 35, 000 persons exposed la tho United States, tad** have found that the Canadian mines employ about 8,000, Elaewhere, U has been estimated that the workers to England who have exposure total bsivesa 3,000 and 5, 000, With workers In Africa, Denmark, Norway, and . pther countries, ax least 50, 000 person's must be exposed throughout the world, ted It can bo aseurood that this number has been fairly constant In the 20 years fleet 1915 when the first cess of asbestosle with lung cancer was reported. JU lull 4 million raaa-yeers of exposure has thus been accumulated, and thle figure can be dlvldod by the approximately 150 cseaa of lung cancer with llltiioili reported during the 20-year period. Thle give* a rato of 15 per |;9,000 which Is at least Indicative that any lung cancer rato which can bo 44 calculated for workers exposed to asbestos duet tf not .much greater than that'for the unexposed population. Comparison Betwoen Eight Counties Adjacent to the Asbestos-Producing Areas snd Hlobt Snlncted Coonttea To compare lung cancer mortality rates la the counties surround' |n| the asbestos'produciag areas with another group of counties in which as asbestos miners are likely to reeldo, the rate's were computed on the basis of figures for the yeara 1950 through 1955. The eight-counties selected let comparison were xrgenteull, Chateaugay, Montmagny, Portncul, Alchliou, Rlvlero-du-Loup, St. Hyacintho. and Terrebonne, mainly because they represent a wide geographic distribution throughout tbo Province. The counties selected because of their proximity to the aobcstoe mines include Arthsbaaka, Beeuco, Drummond, Frontcnac, Megantlc, Richmond, Sherbrooke, sad HsUe, Table )A shows the number at lung cancor deaths for the years ,, 1)50 through 1955 for each of these countlos, and a mortality rate, based on the adulr male population In 1952, To omphaslae the comparison, Megantlc County has boon shown separately, ae has the Province of Cuobec and also the- Province with the eight "asbesUie'producing" counties subtracted. Boceuse . of Us unique lung cancer death rate, Montreal et Ulo de Jesus has also been listed lo order to provide lurlbor comparison. ' 0294 0295 - ' TABLE Jl' - Humber of Lung Cancer Death* and .Rate per 100, 000 Man-Year*' . Counties. McgantlC County* ' - Adult Male - .Population 1952 13,100 Eight HAdJaceotH Countie* 97, 600 Eight Selected Counties Province of Quebec - * 83,000 1,190, 000 Province of Quebec lees Eight "Adjacent" Countie* 1,100,000 Montreal ci laic de Jeeue 399,000 Male Lung Cancer Death** 1950 1951 1952 1953 1954 1955 Total 1t 3 3 I 9 is Rate per 100. 000 96.9 63 9 16 4 16 59 9.4 2 10 5 . 16 5 9 49 ' 9.8 116 220 295 303 303 357 1624 22.6 190 217 37 236 287 299 . 391 192 185 225 1570 770 23.8 32.3 1 II I* uiunxd (hat all male lung cancer death* occur redafter ag*-20. ! i 9 4*. . It Is apparent Irem the table thnt the lung cancer death rate /or the eight counties Immediately surrounding lho ssbeetos-producing arena Is prsctlcally-Hdeatlcnl with that of eight counties eelectod for comparison. White Meg&ntlc County has a rate nearly twice that of the combined eight elected.counties, U W lower than lho rate for the Province, and considerably lower than the ralo for Montreal, The figure for Montreal would certainly be higher except for tho very low numbors of deaths reported for 1950 and l^S.l, and it would appear that la those years some error In reporting has undoubtedly been made. On tho baels of the other years, 1950 and 1951 deaths would bs expected to be about 00 greater. This, would result in a rate of 40 per 100,000. .... . . . The only possible conclusion from this comparison Is that there la ' no ovldonce that tho persons who live and work la tho counties surrounding ' .and adjacent to the aebostos-producing arose'have any greater .Incidence o( lung cancer than those who live elsowhorc in the Province. _ ... - Wecuaelon-^f All Recorded hung Cancer Casos, . .. . . ' : ' Llvtng and Dead, ifrassrtho Asbcetoo Mlnoro ... ' . . - Although a slmplo enumeration of all tho known or suspected casos of cancor of tho lung In theso areas has do particular value from a statistical point of view, U is of Interest to summarise such cases for the record. There were nlno deaths prior to the beginning of the time porlod covered by the tudy, Including ono In which the dfagnoels was mcdlnotlosl lymphosarcoma. 47. During the period cove rod by this Investigation, tho re were nine proved cases and three auspeclod cases In the cohort. Through 1956 and to date In 1957, there were eight doathe, slx of which were merely suggestive ot cancer of the lung and Included euch diagnoses as mediastinal lymphosarcoma, mesotbolloma, cancer of the leg with motestasoe to lung, abaess of lung, and caacor of the pancreas. One other was dlagnoeod on the basis of x-ray only. In addition, there ere now living four cases In which the diagnostic evidence le strongly suggestive of lung cancer. This la total of 33 caeot of all types. Including ten "suspected" but unproved cases, and four that are still living. The remaining 19 constitute the total of proved caees ol cancer of the lung among tho asbestos mlaore since 1940. The proved coses sveragod 59 years of ago at doath, and varlod botwoon 37 years and 6B yeare. Their working span covered periods vary ing from a minimum of 14 years to a maximum of 37 years. Only three men bad less than 25 yeara of employment In the Induotry, Oovon among those on whom euch Information Is available had a weighted exposure placing them In category III, and tlx worked la an exposure represented by catogory 1. There woro only 17 emoag these proved lung cancer esses In which we have Information regarding the presence of asboetosle, Asbestosls was present in nlno. although It was minimal la two. Two pathologists disagreed regarding Its prssonc'e Id another. At least soven of tho 19 proved lung cancers therefore, were not accompanied by asbestosls. 48. Summary and Conclusions Intorcil la the question of whether there may be an association between lung cancer and exposure to aebeetos bee beon evident since the report la 1935 by Lynch and Smith of e case In Which lung cancer and asbss* toele wore both present. As additional cases la which the two diseases co existed were reported, causal association appears to have been gradually accoptod by many authors, although some workers considered the correlation ^te<frW/|iV - to be inconclusive. The present study was comnsloetoned in an effort to determine whether a causal relationship did, la fact, exist between exposure to asbestos and cancer of tho lung. Since most oarller' studies had baen limited to enumerating the .lung cancors found In certain selected samples, such as cases coming to autopoy or death certificates In which aebestosls wee mentioned. It was apparent that V> * * they could not fulfill the requirements of an epidemiological and statistical approach to the problem. The presont study was, therefore,- designed to meet the requirements of this method. After a preliminary ourvey to explore the availability of reliable Information, data were gathered on workers In the asbestos mines In Guebec, . A3 s* n't'** based oa their medical records. A cohort was defined tmxiik.'.ris fertile v /f : r ` r-i"/- A/rc. ` crhoadnand-nit-workerA-wS'^-r-i | ......... . lin t ..... in , &, + / c<t. fr! y>. t/ro<irrryf t*/ ff Data relative to their characteristics were collected and their status at the ' end of a alx-year-perlod of observation was determined. In the case of those who had died, en exhaustive search of death certificate# and Insurance rocords 0298 # .. ......................................................... 49.............................. u carried out la order to. determinen nearly at passible the exact-caute - of doatb. Mortality rates from-lung cancor for the gonoral population of the Province of Quebec and Its various counties and for tho Dominion of Canada, as wall as the United States were calculated from statistics collected In the appropriate places. Comparisons of tho rates obtained for asbeetos workers and for the other population groups .were made according to accepted statistical .irpl.tr. ^ In ................. - ' - * Records were obtained on 6091-persons who fulfilled the crtterla of - tbs cohort. It was not posotble to trace 133 of these for the whole period, bat 5771 of the remaining 6956 were found to bo still living In 1955 or lator. Of tbe 187 known dosd, cancor of tbo lung wae considered to have.been reason- ably proved In nine and to bo strongly suggested in throe, .- ' Tbe members of tbe cohort'wers studied with respect to age, length of employment, weighted average of their exposure, and tbalr smoking habits, Pour thousand, six hundred and sevonty-throo wore found to bo smokers within tho definition of that term as uood in thlo' study,' Thirty-four per.coat of tbe cohort were more than 45 years of ago,' hnd 30% bad been employed for longer than 20 years. Thirty per coat had ewolghtod exposure which placed them In category of highest exposure. - . ' ' ' The mortality rate for lung cancer, as computod on tlio basts of nine "proved" deaths among tho cohort was 25.3 per 100,000, Y/hen tbe three "Suspected" cases ware addad, tbo "total" rale for tbe cohort roeeto 33.8. . -' '* . 0299 ; so. Tbe Importance of the suepectod but unproved cases In determining those ntei ha* boeo reiterated because It It likely that uch cnet would not be Included la tbe statistics for the goacral population and bocauoe they Influence the reoulto eo markedly. -. According to the (lading* la tbU etudy, the mortality rate from lung cancer doe* not appear to tacreaaa with longlb of exposure or with degree of exposure, a f^cX-which presents strong evidence against tbs carcinogenicity of asbcatos. v . Comparleon of the experience among the asbestos miners with that of various segments of the unexpoeod,' comparable population shows that the Observed number of deaths among the miners l* not significantly greater ' than the oxpoctod number. The rate for provod cases among tho ocbectce . miners (25.1 per 100.000) compares well with tho rate of 22. 5 per 100,000 ' for the rost of the Province, and 20.8 psr 100,000 for adult males throughout the Dominion of Canada, ft also compares satisfactorily with rates of 37. 2, 25.3, and 26.0 obtained from various sources for adult males la the United * .i States. Finally, In this.matter of comparleon, It would appear that the world wide experience of persons exposed to esbeetos dust is not worse with respect to lung'cancer than that of the unexposed population. . The counties surrounding the aebestoo-produclng areas, and in which It Is presumed most of the aebostos miners live, have almost Identical mor tality rates with Ibooo of eight counties wldoly scattered through the Province, and are lower than those for the remainder of the Province, and much iowor Chan the rata for Montreal. Sisco 19-10, there have been 19 cases la which the diagnosis of primary cancer of the lung may be considered to have beon proved. Approxi mately half of these cases were associated with asbestosls. All but one disc Is the recognised "caacor-age" sad at least oae-thlrd had only the lightest exposure (category I) to asbeotos dust. ' On the basis of what are believed to be complete and reliable data. It seems fair to conclude that the asbestos miners In the Province of Quebec do not have a significantly higher death rate from lung cancer than do com parable segments of the general population. ' Furthermore, the death rate from dung cancer in the areas contigu ous to the asbestos operations Is comparable to that In areas widely scattered throughout the Province of Quebec and Is lower than In some urbanised areas ' within the Province. 0301  Bibliography 52. 1, Alaaclo, Escobar R. Bronchial carcinoma; review of two hundred case*. J. Intornat. Coil. Surgeon*. 26: 375-379, September, 1956. 2, Alien, hi. L. Bronchlogenlc carcinoma associated with pncunioiio- 'conioels; report of two cates, 3. Indust. Hyg. 16: 346-347, . November, 1934. ' . 3, American Cancer. Society, Inc. Cane or of the lucgl an evaluation of the problem. Proceeding* of the Scientific Section, Annual Mooting, Nov. 3-4, 1953, American Cancer Society, Inc. Now York. 1956. 322 pp. 4. Anderson, C.5, cad Dibit, J.K. Silicosis and carcinoma of the lung. 3. Hyginss. 38: 185-204, March, 1938. . 5. Bander, K.V. Asbcstosie. Deutsche mod. Wochechr. 65; 407 408, March 17, 1939. f hrena, W, experimental asbestosle. 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Aobeetosls and . .brcnchfogonlc carcinoma] report of one eutopsled case and review of available literature. Am. J. Mad. IS: 721*732, November, 1953. 61. Kcnhawey, E. 1~., and Kannaway, N. M. A etudy of the Incidence of cancer of the lung and larynx. J. .Hygiene. 36: 236*267, June, 1936. coot 58. 62. Konnaway, C. 1.. . and Ksnnawny, N. M. Stud lei ol Incidence of * cancer of the ten; and larynx. Bril. J. Cancer. S: 153-138. June. 1951. - 63. Klotz, M.O. Association oi silicosis end carcinoma of the lung. Am. J. Cancer. 35: 38-49, January, 1959. 64. Lam.*, A.J., McConnell, W.J., and Fehnel, J.W. The effects of (be inhalation oi aabeetoa duet on tha lung* oi aabestoe workera; preliminary study, Pub, Health Bop. 50: 1-12, January 4, 1935, 65. Lanza, A.J. Silicosis and aabostosts. New York, London, Oxford - University Press, 1938. 39 pp. 66. Lew, E.A. Vet of life insurance company records for cancer studios. A.M.A. Arch. Xndust. Hyg, 5: 198-203, March, 1952. A 4 ' fL.c.y'?. 67, Linzbach, A.J,, and Wedlor, H.W. Occupational cancer among asbestos workers. Virchows Arch. i. path. Anat. 307: 387-409, 1941. 68 Lynch, K.M., and Smith, W.A. Pulmonary asbestos!*) carcinoma oi lung in aebseto-ellicosis. Am. J. Cancer, 24: 56-64, May, 1935. 69. Lynch, K.M., and Smith, W.A. Pulmonary asbsatoslsi a report oi bronchial carcinoma and epithelial metaplasia. Ant. J. Cancer. 36: 567-571, Au8ust. 1939. . . 70. Lynch, K.M. and Cannon, W.M. Aobestosis: analysis ol forty nocropelod cssos. Die. Cbost. 14: 874-869, Novembor-Docember, 1948. 71. McPbootere, S. B. A survoy ol a group oi employees exposed to asbestos dust. J. Indust, Hyg. and Toxicol. 18: 229-239, April, 1936. 030* -59. ' 72. Mercwtlhar, ,A.A, The occurrence of pulmonsry fibrosis and - 'other pulmonary-affections In asbestos "worker's. J7 Industl Hyg. 12: 190, May: 239, June, 1930. . 73. Mercwether, C.R.A., and Price, C.W. Report on elfecta of aabootoe duot on the lungo and duot suppression in the aabcetos . Industry. London, H. M.S.Q., 1930. 74, Mcrowothor,_E.3l.A. ..Ajos/ttorandum on asbestoeis, Tubercle. 15:'69-80, llovcmber,..1933|) 109, December, 1933j 15( 152, January~l:9J4r'-- 1 1 . ' ' 75, Mcrowothor, . R.A. Annual roporto of the chief Inspector of factories. London, H.M.S.O,, 1947. ; ... 76, Mercwether, . R. A. Industrial medicine and hygiene. 31 London, ' Duttorwortb h Co., Ltd., 1956. 617 pp. 77, Korfmaan, M, The industrial cancer of workero in asbestos. Ztschr. f. Xrcbsforcb. 47: 288-302. 1938. 78, Nordmar-n, M., and Sorgo, A. Pulmonary cancor produced by . ' asbestos dust ln cxperlmentai animals. Ztscbr. X. Xrebsforcb. 51: 168.182, 1941. ' ' ` ^ 77. Phillips, A. J. Mortality from cancer of the lung in Canada. (1931-1952). Canad. Mod. A. J. 71: 242-244, September, 1954. 60. S.-tupu, C, Further contributions to the roentgenological diagnosis of asbestosis. Arch. f. Ucworbepatb. u. Goworbobyg. 9: 391 406, 1939. 61. Smith, K. IV. Pulmonary disability In asbostos workers. A.M.A. Arch. Inditet. 1*73. 12: 198-203, August, 1955. 0^0 ( M . 60. 82. Jimltb, L. W. . Penumoconioala .and.lung .cancer.with .epecial re ference to alllcoala mad aabeatoala. Compena. Med. 2: 3-10, November, 1949. 83. Smith, W.E. Survey ol aotne current Brltlah and European atudlea of occupational tumor prohleroa. Part 111, Aabeatoa. A, Id, A. Arch, lnduat. Hyg.^5: Z4Z-263, March, 1952. 84. . Stoll, K., Bnaa, R., and Angriat, A. Aabeatoala aaaoclated with bronchlogonlc carcinoma. A.M.A. Arch, Int. Mod. 88; 831 834, December, 1951. . 85. Tclcky, L, Der berufllcbe lungonkroba. Acta Unlo Internet. Contra Caocriun, Parle. .3: 253-273, 1938. Aleo, Zentr. Gewerbehyg. Unfallverhut. 27: 33, 1940. . 86. Vorwold, A. J., Durban, T. M,, and Pratt, P. C.' Experimental - atudlea of aabeatoala. A.M.A. Arch, lnduat. Hyg. 3: 1-43, January, 1951. .\ ,, w ft j -- y- ^ > 87. Wcdler, H. W. Aabcatoae und lungenkreba, Deutache med. Wochachr. 89: 575-576, Auguat 6, 1943. 88, Wegdlua, C. Changa In the lung a In 126 caeca of aabeatoala obaerved in Finland, Acta radiol. 28; 139-152, 1947. 89. Werbcr, M. Pulmonary aabeatoala aaaoclated with carcinoma. Zentralbl. Arbaltamed. u. Arheltaachuta. 2: 179-180, November, 1952. 90. Wood, W.B., and Gloyna, S.R. Pulmonary aabeatoala complicated by pulmonary tubcrculoala, Eancet. 2: 954-956, Octobor 31, 1931, 91. Wycra, H. Aabeatoala, Poatgrad. M. J. 25: 631-638, December, 1949. 92. V/ynder, E.L,, and Graham, E.A. Etlologlc fectore In bronchlogenlc carcinoma with special reference to InJuairlal expuourea; report of eight hundred fifty-seven proved caaee. A.M.A. Arch. Indust. Kyg. < 4; 2Z1-235, September, 1951, ' . AFFIDAVIT OF DAVID S. EGILMAN STATE OF MASSACHUSETTS ) ) COUNTY OF NORFOLK ) ss. Before me, the undersigned authority, personally appeared Dr. David Egilman and swore as follows: . 1. My name is Dr. David Egilman. I am over the age of twenty-one years old and am otherwise competent to make this affidavit. All ofthe statements contained in this affidavit are based upon my personal knowledge and are true and correct 2. I am the custodian of records of the Industrial Hygiene Foundation. 3. I have personally reviewed the documents listed below, copies ofwhich are attached to this affidavit and can attest that the attached copies are true, complete and correct copies of Industrial Hygiene Foundation documents. Participants in Seventh Saranac Symposium with attachedAffidavit dated May 21, 1991 ofMichael Rhode, employee ofthe Armed Forces Institute ofPathology, custodian.of original archives ofDr. Arthur J. Vorwald authenticating the listing. (SCF-ALLF-01290) Industrial Hygiene Digest, Industrial Health News, Literature Abstracts, Medical, Engineering, Chemical, Toxicological, Legal. January, 1950 (Vol. 14, No. 1) (SCF-ALLF-01180) Industrial Hygiene Foundation, Industrial Hygiene Digest, Industrial Health News, Literature Abstracts, Medical, Engineering, Chemical, Toxicological, Legal. September, 1952 (Vol. 16, No: 9) (SCF-ALLF-01370) . Industrial Hygiene Digest, Industrial Health News, Literature Abstracts, Medical, Engineering Chemical, Toxicological, Legal. September, 1956 (Vol. 20, No. 9) (SCF-ALLF-01760) Industrial Hygiene Foundation, Industrial Hygiene Digest. April, 1957 (Vol. 21, No. 4) (SCF-ALLF-01830) Industrial Hygiene Digest, IndustrialJHealth News, Literature Abstracts, Medical, Engineering, Chemical, Toxicological, Legal. August, 1960 (Vol. 24, No. 8) (SCF-ALLF-02040) Page 1 of3 Industrial Hygiene Digest, Industrial Health News, Literature Abstracts, Medical, Engineering, Chemical, Toxicological, Legal. March, 1961 (Vol. 25, No. 3) (SCF-ALLF-02140) \ Industrial Hygiene Digest, Industrial Health News, Literature Abstracts, Medical, Engineering, Chemical, Toxicological, Legal. (SCF-ALLF-02310) Industrial Hygiene Foundation, 1967 Annual Report. (SCF-ALLF-02836) . Industrial Hygiene Foundation, 1969 Annual Report. (SCF-ALLF-03082) Industrial Hygiene Foundation ofAmerica, Inc., Report ofPreliminary Dust Investigationfor Asbestos Textile Institute with attached Memorandums on Plant of (various companies) Supplementing the General Report "Preliminary Dust Investigation for Asbestos Textile Institute" ofJune, 1947. (SCF-ALLF-01000) Members ofAir Hygiene Foundation /Industrial Hygiene Foundation as ofNovember 30, 1937 through 1983. (SCF-ALLF-00470) Air Hygiene Foundation ofAmerica, Inc., References to Recent Literature ofIndustrial Diseases, January 24, 1939. (SCF-ALLF-00565) Foundation Facts, Vol. 3, No. 6 with attached Digest ofIndustrial Hygiene, Literature News - Developments, dated June, 1941. (SCF-ALLF-00685) Industrial Hygiene Digest, Industrial Health News, Literature Abstracts, Medical, Engineering Chemical, Toxicological, Legal, Foundation Facts, August, 1957. (SCF-ALLF-01875) An Epidemiological Study ofLung Cancer in Asbestos Miners, Industrial Hygiene Foundation Report by Bruan & Truan; study made possible through a grantfrom the Quebec Asbestos Mining Association (Note: date takenfrom published article), June, 1958. (SCF-ALLF-01939) Industrial Hygiene Digest, Industrial Health News, Literature Abstracts, Medical, Engineering Chemical, Toxicological, Legal, May, 1963, Vol. 27, No. 5. (SCF-ALLF-02375) Preliminary Program, 28th Annual Meeting Industrial Hygiene Foundation, October 23-24, 1963, to Mr. Wagner. (SCF-ALLF-02441) Industrial Hygiene Foundation, 1964 Annual Report with attached membership list. (SCF-ALLF-02468) Industrial Hygiene Foundation ofAmerica, Inc., Asbestos Bioeffects Researchfor Industry, Medical Series, Bulletin No. 11, 1966. (SCF-ALLF-02683) Page 2 of 3 Further, affiant sayeth not. . David S. Egilman, MD, MPH Commonwealth of Massachusetts Norfolk, ss . . SUBSCRIBED AND SWORN TO ME, on this ^ day of May, 2006, to certify which witness my hand and official seal of office. NOTARY PUBLIC IN AND FOR THE STATE OF MASSACHUSSETTS My Commission Expires ---------------- Va \\ Page 3 of3 4 AFFIDAVIT OF DR. HERBERT STOKINGER STATE OF OHIO COUNTY OF ) SS I, DR. HERBERT STOKINGER, being first duly sworn on oath, deposes and says: 1. I am the author of the attached letter. Exhibit "A", which is dated January 20, 1958 from myself to Dr. Daniel C. Braun, Medical Director, Industrial Hygiene Foundation of America, Inc., Mellon Institute, 4400 Fifth Avenue, Pittsburgh, Pennsylvania. 2. I was at the time Acting Editor, AMA Archives of Industrial Health, and the letter was typed on ray letterhead at the Archives of Industrial Hygiene and Occupational Medicine and sent to Dr. Braun. . Further Affiant sayeth naught Subscribed and sworn to before me this day of May, 1992. My commission expires: 4186a:106 *wKutt N. THOMPSON nota>v Puhhc, Suto of oi..u tfv toll!! Dec. ft. ;nw l* 9*m % *v * 1. H lct* Vfffa. I I. lMtn Archirci of Industrial Hygiene Occupational Medicine efface* H . (mi*. I. trni* mminm f#M 4 #M* *1 ltf( Vr*4* IONS. Breednay. CiVmaofi J, Okie, Jenua*7 20, 1938 Or* Daniel 6. Braun Kedleal Brittcr Industrial Kyglsno foundation of Aasrlca, Zac* Kalian Institute, UOO Fifth Aura Pittsburgh 13, PmnsylTsnis . Dtar Dr* Brant Both Or* Mnei and l, hartng reviewed your paper, *10. Xpidosiolefleel Study of lung Cancer In tibiitci Minn1' in platsad to accept it for publication In tha Utt. Archie*s of Industrial Health. Ns find tha roport not only of exceptional lateralt but a artel of tbo epioeaolaglo nstftod la diseases of the lung* . Our only orlUdsa ns that in pursuing the epideslelogio detail the paper beease a trifle long and one got the lapreesion tend tha end that one had raid this before* Z, ayaelf, ne particularly pleased to learn tha aaia con clusion of tha paper na against tha association of lung cantor nth aabootoaia, for X had con to a ainllar conclusion on ob viously far loas Information but vus afraid to say so for this racoon. I as enclosing a review which contains a for aantaneoa that Z Lara sited la this connection ttiat appears in tha Annual Elview of lfedieine, Voluae ?, 1936. leu will recall at this tine evidence greatly favored the positive correlation of lung cancer on exposure to asbestos. Sincerely yeun, enclosure Herbert 1, $tolagr,..>*> - Acting Editor, AKA Archives of Industrial Health