Document 3QL18xBk0M9YM8eYV3BJZbZXx

w IVAN SABOURIN , Q.C. Exhibit Exam of errvlt- I PLAINTIFFS tEX",B,T Offldai Reported |1 OkIHO.00 KATHY RYLANDSHOLf ALDREO BUILDING, MONTREAL. November 11, 1957 Ed. Boadway, Esq., Manager, Quebec Asbestos Corporation, East Broughton, P.Q. Dear Ed, RE: Industrial Hygiene Foundation Study (Lung Cancer)__________` _____ I am enclosing a self-explanatory letter. Kindest regards, j T^V e Abt i\ T ^ Q \\ Enel.: Survey IS/LS ci- | " to. ft . K -------- \l ->-& v^- r COPY November 7th, 18S7. Karl Ltadell, Eeq., Chairman Aiiwrtoa, PM, Dear Karlr- BE: INDUSTRIAL HYGIENE FOUNDATION STUDY (LUNG CANCER!.- Following the annual I. K, F. (Mellon Institute - Pittsburgh) meeting T haw perused advance copy of tho epidemiological survey we otinsted vtth tte L H. F.. I ratios* herswith a copy of the Summary and Conclusion for your confidentlal laformatloa. The whole nmy, In print, will be available In a few days and mailed yon. The enclosed photostat la not of the beat qoaltty and I am atone gaUty la that reapecL I thought yea would be deeply interested la havtag as soon as possible this "summary aad conclusions" which tell os of the substance of the findings la the report which, I suggest. Is well presented, has logical sequence aad Is particularly not unfavourable aad rather effeettwly combats the growing concept of later years la Quebec City (Dr. Vidal was bolding the fort consistently wtth the W. C. XL) la Washington, aad la Europe where It originated and develops most L H. F. seems to haw made the best out of the material available (cancer statistical data were as you know excessively meagre la the whole world aad wry poor tm the Province as report of " cause of death ia no* compellable by law whereas v.g. Tuberculosis most be reported). The presentation of tho eurwy appears objective, to the point, aad I strongly believe Immediate attention should be fives to capitalising upon the report. Ivan Sabourin, Q.C. aldeed building Montreal. * Bari Ltadell, Teq., ViM. -B - COPY Mawatir 7th I9S7 Ths Mjtfwyln ntf Mtf|laftl lilts art mlm (mMpt for tbs word "recorded* at page TtjL tiv. Brava aad tbo*< associated with him Sa this work te my modest epUrtoe haia matte thalr good work. I had a thaare to dlacuaa with i>r. Braun tha suggestions ha salat at tha vary aad. as to Intepeadeat i*Kay reading. This u&st sot ba construed pejoratively aad so as to lacrimiaata tha reading methods of our Doctors at Tbetfard aad Asbestos. Oar staibod is/Orthodox aad U ectoatilicaUy aouad, Objective aad ia ao way aatiquated. At hat the report rathor izxxpltes as to k-ivay reading ia that oar classification has lor object to detaroino the carious edges at s elgalltenat Ubroste of asbestotic nature, "sigaiiicant" meaning a fibrosis having roached a aUge whora it ms) ba said that it coaid play a part ia tha causality af a cartala Incapacity to work (presently or ia the future). Asbestos!* Is ia ear claw a / disease whea it has gam beyond those preliminary atages which are act la theqcselves elrailleant from a compensation potat af clew. The author of tha survey suggests that independent readiAg would taka iaio consideration tha preiiralaary stages of asbestosls (which we eat aside as Iasigait icaat) aad woulo claesily them as eases which would ba reported for a study, each as that conducted by L. h. f. Thus, the reported cases of asbestosls (whether significant or act) would be more cansloo rafete aad the lung cancer Inefctenca would fall below the actual figures - - - but I would ratbor alma suggesting we refer our readings to aa Independent source as 1 firmly believe our Doctors at Asbestos ami Tbatford kUnea are emiaaetiy goaiilied for readings aad that few are as fuailfted aaywhere. Teurs faithfully. tVikUBOUiUH Ivan Sabouein. Q.C. ALDEED BUILDING Montreal. # TL." SUUUAAY AND CONGLUSONC Interest in Mm fMitisn ofvbatbit Omti may W n usociation bstwssn loaf cancer and ubitol er exposure to wb> tea ku btt evident since th* report la 19SS by Lyach tad ** ef a case la which lung cancer aad asbe stools * both primt. As additional cases ta which the two diseases coexisted were reported, # a caoaal association appears to hare been gradually accepted by assay authors, although a few workers considered tbs correlation to be lacoadusire. Cases of lung cancer which had occurred among the as- a4 beatos miners in Quebec had been carefully recorded orer tee years*, sV aad tee present study was commissioned in an effort to determine whether a causal relationship did, In fact, exist between exposure to asbestos end cancer ef the lung. Aeference to tee literature shews a temarkahls uniformity both ef method and of conclusions. In general, gbe method has been to study a circumscribed series sf casss ef afbestosis end to enumerate * those ia which lung cancer occurred. The series may consist ef eases coming to autopsy or sf death certificates mentioning aebestosia, end ' the total number has served ns the denominator by which tee number s of lung cancer cases is divided to produce a certain "incidence rets". This rate, as reported by various authors has boon consistently high, e and its uniformity is Indicated by the following Author Urtirtthr Wedler Vytn Lynch It C Gloyne Totals Asbestos!** D*thi 944 fZ 115 40 lil TlT of Lang 45 fc . I3t1 .# * InHrience tu It. 3 U.8 T. 4.1 .0 Tbs notable characteristic ef all previous publications Is the adherence to tb* development of a percentage rtlikcurt^te a relatively small aad rmrj selected group af cases. Only Doll/*^ among all of tkssa authors, kaa described a representative population group and studied it tor tks mortality tsta trmm loaf tomeOr ami cogs- e pared this rata with that for a control group. Bit Investigation dealt with only 113 man in tks studypopulattcm. * ' Sines most earlier stadias bad keen limited t scamaratia tka lung cancers foundin cartain seiseted samples, feck as eases r ... coming to autopsy or death certificates ka thkk askastoeis was men tioned, it was apparent that they aeold set fnlflM fee NfdrsMSs mi an epidemiological aad statistical approach to tks praJklsm. Tks pre- * * \ * east study was, therefore, designed te feeet feerepdrunUnts Of feU .tbod. ' After apreHminary surrey tC explore Am swraflskCtty mi reliable Informatics, data were gsthacod IP Workers is flee sakeetna V' i , mines in Quebec, based 4* medical records at Ike taro maia locations V V 73 of these operations. Cohorts were defined according to certain cri teria and all workers who met these criteria were included in the study. Through their medical rjecords, data relative to their charac teristics were c, 'lectedand their status at the end of a six-year period df observation was determined. In the case of those who had died, an exhaustive search of death certificates and insurance records was carried out in order to determine as nearly as possible the exact cause of death. Mortality rates from lung cancer for the general population of the Province of Quebec and its various counties and for the Dominion of Canada, as well as the United States were calculated from statistics collected in the appropriate places. Comparisons of the rates obtained for asbestos workers and for the other population groups were made according to accepted statistical methods which have been explained in some detail in section IV. Records were obtained on 6091 persons who fulfilled the * criteria of our cohorts. It was not possible to trace 133 of these for the whole period, but 5771 of the remaining 5958 were found to be still living in 1955 or later. Of the 187 known dead, cancer of the lung was considered to have been reasonably proved in nine and to be strongly suggested in three. The members of the cohorts were studied with respect to age, length of employment, a weighted average of their exposure, and their smoking habits. Four thousand, six hundred and seventy-three .74 were found to be smokers within the definition of that term as used in this study. Thirty-four percent of the cohort were more 45 years of age, and 30% had been employed for longer than 20 years. Thirty percent had a weighted exposure which placed thqm in cate* gory III. The mortality rates for long cancer, as computed on the basis of six "proved" deaths among the Thetford Mines cohort and three a "proved" deaths among the Asbestos cohort, ware 27,6 per 100,000 for the Thetford Mines group, and 22.2 per ltyO.OOO for the Aabeatos group. When the three "suspected" cases were added, the "total" rata for the Thetford Mines cohort rose to 41, >. The rate for the combined cohort was 25.5 per 100,000 for "prored" cases, sad 34 per 100,000 for "proved" and "suspected" cases. The importance of the suspected ' but unproved cases in determining these rates has bean reiterated be cause it is likely that inch caaes would ant be included in fits statistica for the general population, . -^ According to the findings in this study, the mortality rate from lung cancer does net appear to increase with length of exposure or with degree of exposure, a fact which presents strong evidence a- gainst the carcinogenicity of asbestos,. On the other hand, the study ------------------------------------------------------------------------------ . ., indicates that cigarette smoking is a eery imported! factor in ths in- ' cidence of cancer of (he lung. I __. _ . r --* A c umpartrasrcTielatiTe frequency of lang ceacer end as- bestosis is less reassuring, bat we believe that la Dersnse el an .75 under-reporting of asbestos!* cases. The incidence of aabestosis ^ indicated by the medical record* is far below that which would be ^ expected on the basis of '11 previously published figures. Naturally, when the cases of lung cancer are compared with an-artificially low figure, its relative incidence will be higher than it should. However this maybe, 12.5% of the recorded cases of asttestosia in this study developed lung cancer, a figure slightly lower than those quoted by authors who confined themselves to this type of comparison. | Comparison of the experience among the asbestos miners with that of various segments of the unexposed, comparable population shows that the observed number of deaths among the miners is not ; significantly greater. The rate for proved cases among the asbestos ; miners (25.5 per 100,000) compares well with the rate of 2.5 per i | 100,000 for the rest of the Province, and 10. i per 100,000 for adult I males throughout the Dominion of Canada. It also compares satisfadto- it , | rily with rates of 37.2, 25.3, and 28.0 obtain ad from various sources l' | for adult malss in the United States. Finally, la this matter ef com- { ! parison. it would appear that the world-wide experience of persons ex- t | posed to asbestos dust is not worse with respect to lung cancer than that ; ! of the unexposed population. ! The counties surrounding the asbestos-producing areas, and * in which it is presumed most of the asbestos miners lire, have almost identical mortality rates with those of eight counties widely scattered t .76 through the Prorlaco, wad wro. h>* thoa fbaao tdr the QOaaelnder of tho Proriaco, oad mack lowor jfcu tioo rota for htaatewfk '*%* Biaco 1H0V there boro Won #9 a**e to Hick the dfag* oeiii of primary cfacer of * t loaf moy bo coaeiderod to low Wop prorod* Approximately half of tiitio ctm war* wooocifted with oe* .> ; * f beotooio. All bat OM died to the recognised "coacer age" oad ft leoet oae-third hod only tho lightest oxposnro (citafory t) to asbestos daft. Conclusions On tho bull of n coroiul oad detailed ftody of whet in * hollorod to bo complot* ond rolloblo doto, it seems fofr to conclude thot dtf oobostoo miners ot Tbotford Uia^l oad Asbestos It tho Peo- riac* of Quoboe do dot boro o significantly higher deafly tote`from toag cancer thoa do oompoxohlo tegmenta Wf tho goaorol ^optflotiea, Oespirt thio, tho results ^uggest thot o aaiadr ?ho dereldps da disease ooboo- *tosla does bovo o greater likelihood of developing cancer of tho Inag than o porooa without thio dUoon. * respect, howoror, thot wader- roportiag of osbestosis cose* hod lod 00 if fall octets ff*dfg h fda coa- aoction. V " s *1 '* ` The dooth rote front luag canter la tho areas eeatiageoe* to the osbeetos operation* 1* comparable to tbit fa.frees widely orottered throughout tho Proriaco of Quebec oad 10 lowerthan So ohms urbanised oreoi within the Proriaco* '-4% V Q, . j-o * % ; A 4 -4 ' in* f*Vfc. . t .77 The praam* study indieataa feat the effect of cigarette aznokinf ia a mock more important raoeUfretinii in tke production . of lung cancer than ia exposure t^.aabaatat* laad in This respect, it tanda to confirm recant atudiaa dealing with the at&ect of amoldng. Tke value of this luesstigaflte mould be considerably an- a bancod by contigoing the observation of the cohorts forxanlatad herein on a year-by-year baaia. It la strongly roccsrtmended that the cheat x-rays of all workers be submitted to on independent reading for (he diagnosis of asbeetosis, Idace an inaccurately low incidence rate for * . this diaeaaa creates an artiflcaliy high relative incidence for long cancer. t +- .V . 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