Document ZBymox1keZnxMbB96Kdykrjk7

FILE NAME: Saranac 7th Symposium (SSY) DATE: 1952 DOC#: SSY053 DOCUMENT DESCRIPTION: Text of Presentation by Dr. Cartier with Discussion received f.h.hss 5055 HR. CHAIRKAK ARE KEBERS OF THE STKPOSIUK. m J U L U m I was asked to p re se n t a paper on th e to p ic Pulmonary Cancer in the Asbestos In d u s try , n e t on account o f any s p e c ia l q u a lific a tio n s but because I happen to be in charge of a C linic which has as i t s primary fu n c tio n th e supervision of th e pulmonary c o n d itio n o f some 1,030 asb e sto s m in ers; such a group o f enployees working in a small radius of 5 m iles o ffe rs an exceptional oppor tu n ity to study the problem of cancer of the lung in re la tio n to the inhalation of asbestos fibers# PRELIMINARY REMARKS# This q u estio n of pulmonary cancer amonq the asb esto s workers i s as confusing and obscure as th e e tio lo g y and th e p atho g e n ic ity of cancer in g e n e ra l. From 1920 - 1950 th e m edical l i t e r a tu re r e r o r t s a s e r ie s of 5* cases of pulmonary cancer and asb esto s Obviously t h i s l i s t must be incom plete b u t, n e v e rth e le s s , one could ask i s i t sound to think th a t the mere fa c t of d e te c tin g a to ta l of 58 cases of pulmonary cancer during a period of y e a r, i s u f f i c ie n t to e s ta b lis h a ca u sal r e la tio n s h ip when one r e a lis e s t h a t in 1950 an estim ated number of 45,000 men were employed in th e a sb e sto s in d u s try , and t h a t during th a t p erio d a minimum of 100,000 employees have in h aled a s ig n if ic a n t amount o. asb esto s dust? I t is recognized th a t the English s ta tis tic s putlis.. in th e Annual Report of th e C hief In sp e c to r of F a c to rie s f o r the M.E.M 5059 y e a r 1947 aeem to in d ic a te a c a u sa l r e la tio n s h ip between the f a c t o r asb esto s and pulmonary cancer b u t, on th e o th e r hand, in South A frica w ith about the same number of a sb e sto s workers as in G reat B r ita in , and when th e re i s a ls o a la rg e number of a u to p s ie s and good m edical c o n tro l o f a l l employees in dusty tr a d e s , th e s t a t i s t i c s do n o t in d ic a te any abnormal incidence o f pulmonary cancer. I f the frequency of pulmonary cancer in South A frica and in th e Province of Quebec i s r e a l ly not higher amongst th e a sb e sto s workers than in any comparable groups as i t seems tc be, i s i t possible to suspect th a t th e asbestos mining industry might be d if f e r e n t from the Asbestos T e x tile In d u stry as f a r as c a rcin o genic a c ti v i t y of th e asb esto s i s concerned? The f a c t th a t the frequency among th e 30>000 a sb e sto s workers of the United S ta te s who are a lso working in the Asbestos T e x tile Ind u stry i s not known to be h ig h er, adds s t i l l more to th e confusion. Why i s th e sta n d a rd ise d death r a te from cancer of the lungs in Great B rita in 3 tim es higher than th a t in the United S ta te s - 231 in comparison to 723 (ra te s per m illio n )? I t would indeed be very in fo rm ativ e tc have some answers to t h i s l i s t of unanswered q uestions before being ab le to form an o p in io n ; and i t might be th a t a few answers could in flu en ce or modify any conclusion concerning a causal re la tio n s h ip . KtL-tlVtD F.H.H&S -> JTOJULJjJsa.- 5060 PURPOSE OF THIS STUDY. The purpose o f t h i s in v e stig atio n i s to tr y to learr. a , precisely as possible the incidence of p u l- n a n cancer in th e group o f asb esto s mining w orkers; to know th e in d o e n c e in groups of employees w ith severe o r in s ig n if ic a n t exposure and to know th e in cid en ce in groups w ith o r w ithout a s b e s to tic f i b r o s i s . The Saranac Laboratory and many o th e r in v e s tig a to rs were in te re s te d in a complete study which would include an ep id em io lo g ical and an experim ental in v e s tig a tio n arc w..ich woulc perm it to a sc e rta in whether or n ot a re la tio n s h ip e x is ts between th e in h a la tio n of asb esto s d u st and primary pulmonary cancer. This p a te r i s a prelim inary and incom plete rep o rt of th e epidem iological in v e s tig a tio n and th e Saranac M o ra to r y . th e in v estig atio n has been achieved, w ill publish a fin a l rep o rt. METHODS ADD KAT&n.i.ALo. This study was rendered p o ssib le mainly because th ere e x is ts in T hetford Mines a co -o p erativ e in d u s tr ia l c lin ic where a l l th e employees working in the d iffe re n t asbestos com rades a re re o u ired to have a pre-employment exam ination, plus an annual p e rio d ic e x p i r a t i o n o p p le te d each time by a standarc stereogram . At t h i s c l in ic i t was easy to analyse a l l the n e d ic a l re c o rd s, the death c e r t i f i c a t e s , th e p ro to co ls ar.c t i e ^ p a th o lo g ic a l fin d in g s of th e n ec ro p sies and to review the -*- Of ch est roentgenograms of each employee, x h e ^ c ro - m e . ^ a sm all c ity of 18,000 i t *ae a ls o easy to co n tact anc to c . s c - RECEIVED F.H.H&S DATE: 'JUL 3 l 1979 M.E.M isp ira to ry w ith th e tr e a tin g physician the n atu re of any r 50Gi ep iso d e, to have follow -up re p o rts on any sus;: :icus cases and to c o l l e c t a d d itio n a l d e t a i l s on th e cause of :.e deaths* In summary, t h i s study i s based on r e s u l t s and fin d in g s obtained from the a n a ly s is of th e me: cal f i l e s of 3,957 employees having worked in th e asb e sto s Indus: from 2 - 6 0 v e a r s , on the fin d in g s from 53 n e c ro p sie s, or. he d e t a i l s c o lle c te frora th e death c e r t i f i c a t e s , on th e follow -ut e rc rts of cases se n t to sp e c ia liz e d ce n te rs fo r more complete in v estig atio n anc diagnosis. ' I t is p o ssib le, and-more than like!; pulmonary cancer have been m issed; neverthele we have employed a standard procedure in th is th at the re su lts therefore are of su fficien t . that cases of c# we th in k th a t in v e stig a tio n and .m erest to make th is publication worthwhile. RESULTS. Eefore subm itting the re s u lts of th: i t would seem proper to give a few ro u tin e ta reach a b e t t e r understanding of t h i s communic investigation, ir. order tc TABU 1 . POPULATION SAigLED. * cEtVED F H u , * 506- DA1E: J u R U H.E.M ^ - i U S 7 $ Age group d istrib u tion of 5,957 a*beto* worker*. ASI 3ACIDPS Number o f Btployee* 1----------------------- 15 - 19 20 - 29 50 - 59 40 - 49 50 - 69 t 1 t t 76 1115 1091 766 605 60 - 69 70 A Over TOTAL 1 507. 99 595' This tab le gives the age group d istrib u tio n of the population^ani^needs no comment except to mention th a t th e average age of the asb esto s workers i s somewhat higher than th a t o f th e average in d u s tr ia l w orker; i . e . , 35 in comparison to 33 f o r most o th e r in d u s tr ia l groups. This remark i s lo g ic a l when we know th a t the la b o r tu rn o v er in th e Quebec Asbestos Mining Industry i s about the lowest of a ll the in d u stries m th e whole of Canada. This f i r s t ta b le also shows th a t some 2,000 asb e sto s workers are 35 years of age and over - a r e tr e se n ta tiv e group fo r the study of a cancer problem .. -6 TABLE 2. RECEIVED F.H.H&S DMATTE.E.J..U. U- U E J 5 0 C 3 M.E.M Y*ar* employed in the ttb esto s industry by Sf S7 u b e sto e werkere. REUSES: 2,257 men here spent 10 years and over in the asbestos industry. The second ta b le in d ic a te s th e r.unber of years spent in the asbestos lin in g in d u stry by the 3,957 employees stu d ied . Cf course t h i s ta b le i s not as s ig n if ic a n t as one in d ic a tin g th e s p e c ific exposure fo r each employee by c a te g o rie s ; but a f te r many a t t e s t s i t has seemed im possible to fin d a common denominate: which would perm it to add to g e th e r th e y ea rs spent in d if f e r e n t degrees of exposure by the same employee. The man-years exposure has in the mine of many i n v e s t g a to rs no g re a t meaning in g e n e ra l, but in t h i s case th e f a c t th a t 56,456 m an-years asb estos exposure having given r is e to only 10 confirmed eases of pulmonary cancer might in d ic a te t h a t we are net fa c in g an acute problem. The follow ing ta b le 3 shows c l a s s i f i c a ti o n of various . exposures in the asbestos mining industry. I re a liz e th at s-ch a c l a s s i f i c a ti o n could be discussed a t len g th and possibly m odified because in th e asbestos in d u stry , as in most of the 6 0 G j o th er dusty in d u strie s, i t i s im possible to tra n s la te with a s t r i c t mathematical precision the d iffe re n t concentrations of dust p a rtic u la r to each ^ob. This c la s s ific a tio n is given not w ith stan d in g i t s lim ita tio n s because i t is based on dust counts performed by d i f f e r e n t competent agencies and, moreover, because we f e e l t h a t a s a tis f a c to r y c l a s s i f i c a ti o n i s very u sefu l in under stan d in g more c le a rly s c i e n t i f i c and m edico-legal problems. table s . C lassification of various exposure in the asbestos mining industry. RECEIVED f.h .h &s D A T E :^U iJjJ^ M.E.M Estimated degree of hazard. 0 1 z Industrial Operations AILCSrHSKIC Total dust count j rercent i.P .y.C .F . of air fiber count. sampled. Open P it, Shops Less than 1 Open P it: Box Loader, Cobber Dump Primary Crusher Dryer Concentrating Underground: a ll 3^* under v e t conci tier.. Short exposure of sk ille d employees 1 -3 1- 3 2- 3 2 -6 2- 5 3- 6 Open P it: dry d r illin g Secondary Crushing Storage Bin 2 -5 1C - 12 10 - 14 Less than 2 Less thar. 2 Lees than 2 5 6 cV 1- 2 1 -2 4 -6 4 -6 5 Underground: dry d r illin g G rizzlies Shed Cobbing Shipping Shed: Cleaners, F ilers ID - 15 5-15 3- 5 4 - 15 1- 3 2 14 - 16 10 - 14 4 KT eilslt:erLs.illw righ ts, O ilers, Sweepers. 1 0 -82 5 2520 5 Bagging Department I Z - 30 26 l______________ KHCEIVED f.h.h &s . -s- DATE. JUL 3 , 1373 500; M.E.M , This ta b le in d ic a te s th a t th e t o t a l dust count anc the percent fib e r count are both co n stitu en ts of the degree of hazard, meaning th a t a r a th e r low t o t a l d u st count may become a ris k when th e percen tag es of f ib e r s i s high and in v e rs e ly , th a t a high t o t a l d u st count may a ls o become harm less in producing pulmonary f ib r o s is i f th e f ib e r percent count i s low. The percentage of f i b e r s in r e la tio n to the t o t a l count i s c a lc u la te d f o r f ib e r s 5 m icrons and over, and on the p rin c .p le th a t only p articu les having a length at le c s t twice it s wicth ere f i b e r s . As you may see in th e ta b le , the in d u s tr ia l o p eratio n s a re grouped in 6 d iffe re n t categ o ries anc these categories are ag ain sub-divided by a double lin e in two main groups. *he unper group in clu d es the jobs w iieh in our experience do not produce f i b r o s i s o f some c l i n i c a l im portance and th e lower group the jobs which can produce a sb e sto sis. There is an obvious ex p lan atio n why the ner. working in th e open p i t do not develop a s b e s to s is and a ls o why th e net. work ing as baggers night develop a sb e sto sis, but i t is none ccfficu.it to e x p lain why some in d u s tr ia l o p e ra tio n s w ith about th e sate oust c o n c e n tra tio n as secondary cru sh in g , sto rag e b in or. one p a r t, the g r i s s l i e s and ahed cobbing on th e o th e r p a rt have been c la s s if ie d in d if f e r e n t c a te g o rie s . We admit t h a t in adopting such a c l a s s i f i c a t i o n we have been in flu en ced by our c l i n i c a l fin d in g s to some e x te n t, but a lso by th e f a c t th a t in the o p e ra tio n s of category 3, th e f ib e r co n cen tratio n i s more constant and work much heavier th an in the o p e ra tio n s of category 2. There is a marked d iffe re n c e -9- RECEiVED F.H.H&S DATE; Jilt 3 ^ B7Q 5C6J M.E.M in th e degree of hazard o f c a te g o rie s 1,2 and 4 and 5, but the d iffe re n c e is not so narked f o r th e c a te g o rie s 2 anc 3. This ta b le is important in order to fu lly understand those to follow. I t is tru e th a t the main purpose of th is p re se n tatio n i s to re p o rt the in cid ence of pulmonary' cancer in a group of 3,957 asb esto s w orkers, but th e nude statem ent th a t 10 cases of pulmonary cancer have been d e te c te d would not be s ig n ific a n t u n less we can compare t h i s prevalence w ith th a t in. comparable groups. This ta sk o f fin d in g a good conparable group cr a c o n tro l group in t h i s study as in any s im ila r stu d ie s is very d i f f i c u l t . We wish i t had been p o ssib le to fin d a co n tro l group in-other in d u stries or in other in d u stria l centers in the Province o f Quebec or elsewhere in Canada. V,'e soon re a liz e d th a t no o th er in d u s trie s were in te re s te d in th a t problem of cancer of th e lungs nor did they have the necessary d ata f o r comparison. No o th e r in d u s tr ia l c ity has ever had tw o -th ird s of i t s male ac u lt popu.atic o f the same age group so c lo se ly m edically supervised w ith a c l i n i c a l and ro u tin e rc-er.tgenograthic exam ination as has been done in T hetford Mines f o r th e l a s t 7 y e a rs . The mass surveys m d if f e r e n t c i t i e s did not h elp the s itu a tio n ; the fin d in g s were toe d ific ie n t doubtless because a too small proportion m the 4 0 -year and over age group i s ta k in g advantage of the mass survey. As a m atter of f a c t , a mass survey in Thetford Mines in 1950 by th e P ro v in cial Department of Health did not detect a single case o f pulmonary cancer as in most of the other c e n te rs, enc the ar.aly of the re su lts is not very h elp fu l. RECEIVED F.H.H&S - 10- DATE: J U L 3 1 1979 M.E.M I t seems probable th a t th e g en eral in cre ase in the 50G7 frequency of lung cancer i s not purely ap p aren t, but when we observe in many c i t i e s a sudden and im portant in c re a se in the lung cancer m ortality ra te s such as the increase in th e City o f M ontreal from 7 .7 in 1946 to 12.9 in 19^9, we must admit t h a t th e m edical d iag n o sis f a c i l i t i e s are re sp o n sib le to an appreciable extent fo r such an increase* Therefore the exclusive a n a ly s is of death c e r t i f i c a t e s in v ario u s c e n te rs which do n et have the sane medical f a c i l i t i e s , has to be used with caution n o t should i t be used u n less th e f a c i l i t i e s are comparable. In th is study the comparative s t a t i s t i c a l analysis of the death c e r t i f i c a t e s was not used because in th e opinion of th e c f f j.c - e l s t a t i s t i c i a n of the City of M ontreal and of the S ta tis tic ia n of th e N ational Cancer I n s titu te of Canada, the death c e r tif ic a te s of the asbestos group consisted of a highly s e le c tiv e group and a s im ila r s e le c tiv e group was not a v a ila b le elsew here. For a l l the reasons m entioned above and the f a c t of b ein g unable to make a b e t t e r s e le c tio n , we decided to compare tne in cid en ce of pulmonary' cancer in d if f e r e n t groups of asbestos w orkers who have been subm itted to th e same medical investigation, and who a t th e same time were p re se n tin g enough; c h a r a c te r is tic s to permit certain conclusions or imprfesiions. TABLE 4 . RECEIVED F.H.H4S PATE: J U I j , IQ7Q M.E.M . Incidence of pulaonary cancer according to degree and length of exposure by age groups. D0 v S GROUP L. U nsignifleant exposure GROUP 2. . Significant exposure liuzber of Employees ! ------------.--------- i Prevalence of Pulmonary Cancer AGP GROUPS 16 - 55 40 - 66 2225 1567 0 6 (0.4451) AG Gault'S ... 16-55 56 ! 40 - 66 i li j 505 | 1 . 0 j 4 1 i RSJ&KS: Uniigrifleant exposure includes ir.en wit:, exposure 0-1-t and less than 15 years 5-4-5. Significant exposure includes only cer. with more than 15years 5-4-5. (See Tatle 5) The u sual c a lc u la tio n s of the stancarc e rro r sho\% t..s~ the observed difference in percentages of incidence in the 2 groups (.87) i s in f e r io r to tw ice the Standard Error (1 .3 h6 ). This ta b le shows t h a t th e re i s no s t a t i s t i c a l evidence th a t the incidence of pulmonary cancer in the group 2 including th e employees who have su stain ed severe exposure and a l l these wh, have also developed a sb e sto sis, is higher than in group 1 of employees th o se w ithout s ig n if ic a n t exposure and w ithout any clin ical asbestosis. RECEiVED F.H.H&S PATE-J W L 3 i 197P a t GS -1 2 - M.E.M I t is recognised th a t th is ta b le might lose a large p a r t of i t s meaning i f i t i s hhown t h a t any in te n s ity of a sb e sto s in h a la tio n o r any amount of a s b e s to tic f ib r o s is could be considered as ean cerig en ic because then a la rg e number of employees in group 1 w ill be tr a n s f e r r e d to group 2 and i t i s probable th a t an unknown number o f pulmonary' cancers in the group 1 would also have to be tra n sp o rte d to group changing r a tid lv the observed d ifferen ce in incidence as well the conclusion. . As a lo g ic a l comclenent to t h i s ta b le , we wish we could give a long s e rie s of other ta b le s showing the incidence of pulmonary cancer in groups with recen t or remote exposure; in groups w ith gradual exposure o f 1*2 to 15 y ears or a s im ila r exposure of long d u ra tio n , 15 years and o v er; a lso in groups w ith ex ten siv e exposure and a s b e s to s is or w ithout a s b e s to s is . The d ata obtained from such ta b le s m ight t e l l us in the hypothesis of a causal re la tio n sh ip whether the inhalation of asb esto s dust i s more im portant than the presence of a s b e s to s is i t s e l f also what approxim ative degree of a sb e sto s in h a la tio n can be considered as predisposing to cancer. -13- JC?s 0 IAB1X 5. Comparative Incidence of Pulrontry DECEIVED F.H.H&S DATE: J U L 3 i 3979 M.E.M Cancer in 2 groups of 52 Autops'ied asoestcs workers. --------------------------- i-- 1 GROUP 1. Employees with Asbestosis Kunber Autopsied 34 Kumber o f Ironary 4 Cancer Percent in Each Group GROUP 2. Sr.pleyees without Asbestosis IS e TOTAL ew*v 10 v* +*, ewer/f This ta b le shows the prevalence of pulmonary cancer ir. a s e r ie s of 53 a u to rsie d a sb e sto s workers having worked in th e asb esto s mining in d u stry from 17 to LO years in d iffe re n t degrees of exposure. This s e rie s of a u to rs ie s i s net as im portant as the s e rie s published in the Annual Report of Great B rita in fo r the y e a r 1947, but can be considered as le s s s e le c tiv e and more re p re s e n ta tiv e in n o t being composed frem cases of asb e sto se s e x c lu s iv e ly but composed of a l l th e employees who happen -o be a u to p sie d ; although i t should be mentioned th a t th ere was an RECEIVED F.H.H&S DATE: *JUL 3 l 1979 5071 - 14- M.E.M in v o lu n tary se le c tio n in the sense th a t most of these employees have been au topsied because they were p re se n tin g some re s p ira to ry symptoms. This c o in c id e n ta l s e le c tio n might ex p lain to some e x te n t the high percentage o f cases o f a s b e s to s is , but in many in s ta n c e s the amount of a s b e s to tic f ib r o s is d etec te d was descr as minimal and o f no c l i n i c a l im portance because n o t s u f f ic ie n t to produce symptoms. Because the observed d ifferen ce in percentages of incidence is in fe rio r to twice the Standard Error, th is tab le does not reveal a s ta tis tic a l evidence of a causal relatio n sh ip between a s b e s to s is and pulmonary can cer. Unless we have th e c p ro rtu n ity to per ferr. an autepsy c-n a l l enployees who d ie , i t remains d i f f i c u l t tc expxain wn} in our se rie s th ere are le s s cases of pulmonary cancer in the a s b e s to tic group and I th in k we have here a gocc i l l u s t r a t i o n as to why many s t a t i s t i c i a n s counsel not tc craw any conclusions from s t a t i s t i c s based on a s e le c tiv e group even i f such a group be in th e 'au topsy1 category because the r o le rlay eo by th e fa c ie : co-incidence might be too g re a t. 15- IA5LE 6 . Deaths from Pulmonary Cancer as a proportion o f deaths from Cancer of a ll s i t e s . 1S40 - 1950 M.E.M - -> 5 | 1n7Q Huaber of Cancer All fonts Province o f Quebec City of Lontretl City of Quebec City e f Thetford Hines 45643 15247 2543 172 Huaber of Pulmonary Cancer 1593 918 94 9 Percentages 3.2 6.0 3.7 5.2 Table 6 was prepared fo r th e purpose of determ ining i- th e r a t i o between the number o f cancer deaths a l l s i t e s anc tne pulmonary cancer deaths was somewhat d if f e r e n t in Thetforo lim es from th e r a t i o observed in few other c o n tro l groups. 'F i r s t i t should be mentioned th a t about of the cases of pulmonary cancer in M ontreal and 1C0S of th e cases of the Thetford Group a re autopsy cases and both c i t i e s have th o rac ic c lin ic s , so th e s e two groups are reasonably com parable. In Quebec City f o r th e s p e c if ic period 19^5 - 1950 in c lu s iv e , 5;* of a l l can cer deaths were a ls o pulmonary can cer. I t was thought th a t had a s p e c ia l f a c to r e x iste d in T hetfcrd Mines the r a ti o between th e number of t o t a l cancer and th e number of pulmonary cm cer would have been d if f e r e n t . The d iffe re n c e observed here is n o t s u f f ic ie n t to draw any conclusion e i t h e r p o s itiv e ly c. negatively. TABLE 7 . Comparative 10 Year* Expectancy and 10 fears PreTalence of Pulmonary Cancer in 2 c i t i e s . RECEIVED F.H.H&S DATE:J U L J j _ ^ 7 M.E.M PLACE Thetford Lines Montreal YEARS 1941 - 1S50 1941 - 1950 10 YEARS EXPECTANCY 10.5 6S3 10 YEARS PREVALENCE 9 856 Based on E.S. Public Health Serviee Report 2537. A random population of 48,833 giving a year pulmonary cancer expect ancy of 7 cases per 100,000 population. Table 7 was prepared a t th e suggestion of Dr, P h ilip p s , S t a t i s t i c i a n fo r the N ational Cancer I n s t i t u t e cf Canada who th in k s th a t the comparative study of th e 1C years expectancy anc 10 years actu al prevalence o f pulmonary cancer in Thetford Mines and in M ontreal w ill be more in fo rm ativ e and more conclusive than analysis of the m o rtality r a te s . According to the surfey of Dr. Dorn, ta k in g random p o p u latio n of 48,833, an annua- i n c i dence of pulmonary cancer of 7 cases per 100,00C can be expected, g iv in g a year expectancy of 7. I t is tru e th a t Dr. Dorn' s survey was made in 1943-45 and th a t the y ear expectancy might have in c re a se d re c e n tly . As a m atter of f a c t , Watson of Saskatoon, Canada, found in 1948 a y ear expectancy of 8 .5 ; th e r e f o r e , a year expectancy of 7 is a rath er conservative standard. . On th a t b a sis Thetford Mines with an average population o f 15,000 fo r 1940 - 1950 period i s supposed to have 10.5 cases KtCtlVED F.H.H&S - 17- * - M i i isis M.fc.M sc>:( ' o f pulmonary cancer, and th e a c tu a l prevalence i s 9 cases. Again i t seems lo g ic a l to th in k t h a t the 10 y ear prevalence fo r pulmonary cancer in Thetford Mines where tw o -th ird s of i t s ad u lt p o p u latio n is working in the asb esto s in d u stry would be higher th a n th e normal 10 y ear expectancy, should the f a c to r a sb e sto sis be considered carcinogenic. SUMMARY. The e tio lo g y and the p ath o g en icity cf the pulmonary . cancer in r e la tio n to a sb e sto s f a c to r is as obscure and confusing as th o se of cancer in g en eral, and in presence c f co n trad icto ry d a ta , th e many d if f e r e n t asp e cts of th e problem should be co n sid ers before arriv in g at a conclusion. The purpose of t h i s study i s to le a rn the incidence cf pulmonary cancer amongst th e 3,957 asb esto s mining workers anc to compare t h i s incidence with o th e r comparable groups. This in com plete ep id em io lo g ical re p o rt i s a c o n trib u tio n tc a more complete in v estig atio n under progress at the Saranac Laboratory. According tc the standard procedure the medical f i l e s , the re s u lts of medical supervision, the annual stereograms of a ll th e a sb e sto s workers having worked from 2 to 60 years and the fin d in g s o f 53 au to p sies have been used as m a te ria l. The r e s u l t s have been ta b u la te d and compared to cont*ol groups and we th in k th a t th e d a ta c o lle c te d ir. th e Asbestos Mining In d u stry are not exactly superposable to th e re s u lts found in the - 13- sDATsE:n i f f i a 50V M.E.M E n g lish Asbestos T e x tile In d u stry of Great B rita in and i f they do n o t perm it to deny a cau sal r e la tio n s h ip between th e in h a la tio o f a sb e sto s dust and th e occurence of pulmonary cancer, they do n o t seem e i t h e r to b rin g any p o s itiv e evidence. tty DOCTOR RHOADS: The n ex t paper on the *.-? - _ concerns the paper alread y d isc u sse d by Doctor Hu-.per. K v could have a l i t t l e e u ie t, i t would be very h e lp fu l f o r those who are p re s e n tin g p a p e rs . D octor Huepe. ha. a ____ , t ev'tiV we t.us t defer t..--s si..-- D octor D rin k er's rem arks. I b-" M we can g et the papers under way. ^ I W ill, th e re fo re , in troduce the paper or. a s .e s - to s m ining by Doctor C a r tie r . Doctor C a r tie r . ' t v nnr^O? CABTSK? Members of th is Tynposiur.: I t i c i a n , n e ith e r an ep*ae.A--l o tei- m have accepted to present th is paper, io. b e _ .t ^ ^ don't think I shou-c but I tn in ,-^ to ^ e ^ icyself* I should say th a t th is s.a ^ S w -c - an ^ p apers I ar. p re s e n tin g have beer, reviewed by 7 * - tic ia n in M ontreal and Doctor P h illip s , o f f ^ a l -** s " ' r o r n a tio n a l Cancer -TInws,e.*i^-*t--ote oe.' Cc anaca in T o .----- -.. - - _ u._ a,v the r e soons-o--.*.-0,; would lik e th a t th ese two e x p e rts - - ef the statem ents I might advance. so 1 was in v ite d to p re se n t th is paper on ne ' . v . , a - ^ / n c in d u s try , not on pulmonary cancer in tne asw - - * * . ,, ' - i ^ r s t i o n . onlv because I ha.pe.. account of any s p e c ia l q u a u lfio a tio .,, . . v, . . . o ' a c l i n i c which h a s, as a p. -- J - to be in charge o. a o il. thousand tio n . to supervise the primary oon-ition o. f . ft-rfernne an ..V i.stos m iners, such a group of en tra n t t a i e ; from page 3Bi. r eceiv ed f.h.h&s DATE: 31/L 3 | M.E.M BY DOCTOP CAETXEH Menbere of th is Symposium: Kot being a statistician, neither as epidemiologist, I don't t hinl; I should hive accepted to present this paper, b it X think, to excuse myself, I should aey that this sta tistic s and most of the pipers I ar presenting htve been reviewed by your statistician is Montreal and Doctor P hillips, official statistician for National Cancer Institute f Canada is Toronto, so I would like that these two experts take the responsibility of the statements I sight advance. So I was invited to present this paper on the pulmonary cancer is the asbestos Turing industry, not on account of any special qualification, only because X happen to be in charge ef a clinic which has, as a primary function, tc supervise the primary condition of four thousand asbestos miners, such a group f entrants offering an RECEiVLD F.H.H&S , c DAIE:JHLLd22L- ' M.E.M o u ts te n ding met e l l u r gi c e l study of ear.ce? o* tne -*~S - re la tio n to asbestos fib e rs or ary other re la te d fib e rs . in the o rig in of m ines, . i t d if f e r e n t comoar.ses are doing asb esto s mining o p e ra tio n s, so for more tnan eigh ty y e a rs , and since 19U5. these c o p i e s have organ ised the Thetford Industrial C linic v..ic.. n a ., a- P mary aim, to f u l f i l l a program of in d u s tr ia l hygiene, mainly medical and w ith dust co n tro l p ro v isio n s. In 1950, the concept of an Inhalation of asoes- to s f ib e r s and pulmonary cancer vas mentioned by many^in- v e s tig a to r s and i t vas a t t h a t moment th a t the Keoscal A dvisor or the Quebec Asbestos Mining Associe ,,io.., se -O a 7 e rs, to recorrr.end vantages f o r the employees ana tne _ - e- o io sical anc . company in v e s tig a tio n composed o. an e r i c ... S- gjqpgj*jjiicntal study* This re p o rt is p a rt of th is study. The T h etfo re. Iwn a*u -t. ia}. rC"--< iic has been in opsr* . t i o n only since 19i 6, and ve have m edical reco rd s on^ v^ thousand fifty -tv o employees, b u t th is survey is b is e s _ ^ - ' . j seven workers hav-ng on three thousand nine hunored fix WM* e d in the in d u stry from two to s ix ty y e a r s , .b o u t o r, thousand employees have been ra ja a ta d from th is curve., ^ e , . _ *-oucha or becam e tne., cause they have n o t worked long e-ouen, hs,, worked in d if f e r e n t in d u s tria l trad es b efo re. c-vmm. p re se n tin g the f i r s t ta b le , 1 t h -- IKSVED F.H.HtS __ --------------------------------- -- ---------------:-----------0 W t ' J l l t 2 3 3 2 . .U* worthwhile to say th at the labor turn-over in the asbestos In d u stry i s one of the low est in a l l the in d u stry in Cana da, meaning th a t the s ta b le population is working in our Bine and meaning, a ls o , th a t in many a s p e c ts, i t i s e a s ie r to study and more r e p r e s e n ta tiv e . The f i r s t s lid e p le a s e . So as I mentioned, *n.s Table Humber 1 shows th e age group d is tr ib u tio n o f the group study a n d 'I d o n 't th in k i t needs any ce m e n ts except to say th a t the average age of our employees is th ir ty f iv e , about two yaars o ld e r than the average Tor the gener a l in d u s tr ia l p o p u la tio n , and th is ta b le w ill show also t h a t 1,577 men are Included in theage group from fo rty to . and over, in the group where theincidence of cancer is more g e n e ra l. _ Second -- next ta b le , p le a se . This tab le in d i c a te s the number o f y ea rs sp en t In the asb esto s mining in du stry by the t o t a l number of employees surveye-- 0. c th is ta b le is n ot as s ig n if ic a n t as would be a ta b le t a i l eatin g the sp ecifio exposure of these employees, but a fte r nany attem pts i t h a. ...m .d im posaibl. to - to add tog.the the d iffe ren t y ear, spent in d ifferen t concentration of f i b e r ., to which moat of the am ploy.es'have been exposed, and I th in k as a remark to o , i t i* wwoorrtmhwmhile to mention th a t two thousand, two hundred have spent more than ten years in the asbestos industry. RECE!VtO F.H.HiS tktl 'ft)L T rE 79 M.E.M n e x t ta b le , F le e s e . The fo llo w in g tE :le 6 c la s s if ic a tio n of various exposures In the asbestos mining in d u s try . Re d i e th a t th is c l a s s i f i c a ti o n could be d is cussed f o r many h o u rs, and p re se n t many q u a r r e ls , b u t I th in k n e v e rth e le ss th a t we need, fo r nary p-utposes, we n a s i , Job C la s s if io a tio n , even fo r the exposure asp ect or fo r re s e a rc h , so a f t e r we were s ta tio n e d v itr. cur e r fc-nee. , took the average of a l l the dust survey made in the r.in - in g in d u stry arc*. .w.,,e a e c io e - j u - * to draw th is ta b le , an*, th is ta b le has ails o , x doni'tt ikrnnoowv iuf it i s o bvje c tiv e adv an tag e, b u t has th. e ac-vantage oA rcoo.t.-ee.C1awti-nneg w ith our case of asbestosis* _ I want to s ta te th at all. the cases of a sb e stc sis have belonged - have worked in shops, under th a t r u le , IT . s o rry , in the lower t r " ? . and our nen having workea even rr0 two to f o r ty - f iv e y ears in th a t kind of exposure, has never developed an a s b .s to s is whioh was found by p a tn o .o g . c r ep id em io lo g ists o r by experim ents, to be of any sequen Uiy m edical sequence* This ta b l e . y * ?reseatS m iUl0r- t i d e s p ar cubic fo o t and the percentage cf fib e r count. This i . very im p o rtan t, b .c e u s . from, a x p .ria n c . to exper- . i.n o e , i t ...m s th a t the fib e r is the only p a th o lo g ic .^ agent* rock. d u.s..t nnoott. bbeeiinngc - n o t being reproduces. in any^ eoneensus. pu,,lmon'ary,, if.iicvr-oftSsil Ss .. T1 tth--in k ,, only. th is n * n t JDEiVI& fJUi& $-3S5. DATE: J U L L l J I i M.E.M need sons f u r th e r e x p la n a tio n , because you see th s t is not e l e s r . Even th is might seen s l i t t l e le s s concentrated, h u t J u s t the sane ve p u t in th is whole group, because on th e ground, dry vor1c and the g r i s t l y men are wording lo n g e r, they are working In none constant concentration of fib e rs , and In the t h ir d p la c e , because we have found a few excep tio n a l cases o f a s b e sto s is in th a t group. So, please r e member the c a te g o rie s , 0, 1 , 2, 3. k =* 5, because in the coming ta b le s , they m ight help you to understand them. The fo llow ing ta b le s in ten d to in d ic a te lndicenee or prevalence of pulmonary cancer in d iffe re n t groups of asbestos workers in comparison to d iffe re n t control groups. The ta s k of s e le c tin g s ig n if ic a n t c o n tro l group has been, in th is ea se, as everyw here, r y d i f f i c u l t , V* would have wished to be able to fin d a group in the province o f tu e b e c , a group in any o th e r com parative - comparable in d u s t r i a l group, b u t i t was im possible f o r the follow ing re aso n , t h a t in no o th er in d u s t r i a l c i t i e s in Province C.uebec, so larg e a proportion of the ad u lt population is followed m edically so clo sely , because I think I should mention to ycu th a t about th irty -th re e - about th irty percent of the ad u lt population in Thetford are working in the mines, being the only in d u stry , so w. can.-t have a very close supervisees e f the function of the - of the condition of the lungs. u . t r i e d , w ith th e mess survey, to d e te c t a com- w.u* p a ra b le survey group, t u t I d o n 't th in k I t was o. is pos s i t l * . because In th e Province of Quebec, very few ad u lts over f i f t y y ears o f age are ta k in g advantage o f th e mass su rv ey . As > n a t t e r o f f a c t , the mass survey made in Thetfo rd mines in 1950 by the P ro v in c ia l Department of H eaitn , did not d e te c t a sin g le case o f pulmonary cancer, e ith e r in the g eneric o p e ra tio n or in fo u rte e n miners whs have been X -rayed, so having not succeeded in s e le c tin g a goou con t r o l group fo r the re a so n J u s t m entioned, we have decided to make com parative study of incidence of the pulmonary cancer in d iffe re n t groups of asbestos workers, which can be s tu d ie d w ith th e same methods and which, a t the same tim e, would p re se n t s u f f ic ie n t c h a ra c te ris tic s to be s ig - n ificaat. The n ex t t a b l e , p le a s e . This ta b le in d ic a te s ^ p rev alen ce o f pulmonary cancer according t o c e 6ree o. le.nt . to degree and len g th of exposure and by age. This ta b le ^ shows the prevalence of pulmonary cancer in the group v ..h evere exposure, tt hh aa tt''s, t h i s groum. .. and th is i s more or le s s a control group. . T h is, W have a ix cases of pulmonary - of primary pulmonary cancer and four eases, in fa c t, in the group ex - p e ,, d and t h i a , o f c o u rse , th e number being sm aller, i t gave u a h i goer in c id e n c e , b u t i f we also take th a t, we wav. to admit th a t th is d ifferen ce in incidence i s not, nas RECEIVED D M E-joi1 ; ifu _ M.L.M no s t a t i s t i c a l valu e, because I t is n et core or ecus! to twice the secondary condition. Kext, p le a s e . This ta b le was nede a t the sug g e s tio n of Doctor P r a t t , who was in te r e s te d to know the com p a r a tiv e in cidence in group cf eaployee, of employees wao have been exposed to a sig n ific a n t oegree of exposure, Category 3. K 4 S. ** le s 5 ' " 6:14 ^ " 4" a c o n tro l group, we take the group of employees w ith eny k in d of exposure, but or the C ategories 1, - 0, 1 and 2 . Doctor P ra tt had in cir.d, in suggesting th a t ta b le , th a t the fa cto r exposure to severe concentration of a sb e sto s f o r any le n g th o f tin e n ig h t be as s ig n ific a n t as the fa cto r asb esto sis i t s e l f , neening th at i f there i s a possible eausal re la tio n sh ip , the inhalation of s u ffic ie n t dosage of asbestos fib e r s n ig h t be as im portant as the f a c to r a s b e s to s is i t s e l f and a t the sane t i n e . 1 th in k we have the two extrem es. In th e previous s l i d e , ve have ne.n with severe exposure, the incidence of esneer, pulnonary cancer in nan w ith eevere exposure, and in th is - in th is t e s l e , we have en in the group 2 w lth very lig h t or very l i t t l e exposure b u t w ith s u ffic ie n t dosage of - of dust. K elt ta b le , p le e e e . This tab le indicates tne prevalence of pulnonary cancer in a series of fifty -th re e autopsied asbestos w orkers. This a n a ly sis, .1 though not a ID < cpr=.\LD ^ 1 iJi'> V..U im portant as th a t of Doctor Kerevether of Great D ritstr., i s b ased o= q u ite a s i r c a r b a s is and I " ^ .in l: - .a t t h i s group is le s s s e le c tiv e , because th a t i s no secai^.a a t all* T h at's a l l the cases ve meant to autopsy a fte r - from f i f t e e n y ears and over in tne in d u s try . Afca .n h e .e , the difference is not as b ig as i t looks, beca-se a .te r u sin g - u sin g the stan d ard th e re , we cane to a o if,e re ..c e of about only $ -between the two groups, tne group w__. asbestos is and group w ith - w ithout a sb e sto sis. 1 can n o t answer why th ere is le s s cases of can cer in the a s b e s to tic group, b u t I th in k th a t i f ve could ^ have autopsy on every employee who happens to c .e , we - e r g et e ith e r a d if f e r e n t p ic tu re o f maybe an indirecw em?-su. a tio n . Kext ta b le , p le a se . This table vas nede fo r the purpose of taowtns i f ^ " S* cer deaths o u tsid e and the pulmonary cancer c e c - s wfcs acnewhat d if f e r e n t f r c n th e r a t i o observed in a few other control groups. F ir s t, I think i t should be nentior.ed th a t ninety percent of the eases fo r the City of Kontrea. and a hundred p e rc e n^t o*f *thve .eeeesiecs ffon.- tthnee Co itv. of T het- fo rd Mines, ere a u to p .i.d , are p o st norten cases, so tnat i , *hy 1 say i t i s d i f f i c u l t to con?e r e . 1 d o n 't l=ov ir. which p ro p o rtio n fo r ttnhee rPrrovince or City of Quebeck, cut fo r the P rovi.n ce. of a>u.,e.v-eeCc(, the s*t a t i s t i c i a n and the . . .... - t th sane tin e to ld roe tvh---a t l--e-s--s than ter. epidem iologist at tn . s ^ be ^ p ercen t are post-mortem eases, -o t -- . * v t T tb<nl: 1- th e re vas a~y perat-le to a U rge extent, b - t I t - s ig n if ic a n c e , we should expect to have a . - in the percentages. Her.t, ta b le , p le a s e . In -te a a o* . ^ annuanl pprreevvaalleennccee vor.. incidence of puxnonary_ c&-*c~- --Vftv> ^ Vu v the incioer.ce in p o p u latio n oi T hetford Mines v it* . t . - * ,r . .. ,v ^ t the R ations- Cance. co n tro l groups, Doctor Pr.. x.. - * * ^ +v, s Institu te of Canada has a.^,5 suggeste to VC*-'*/ tlii* * *** V- V i s v ase - on t i e f a o t t h a t Doctor v=nr.i..s has ta b le , which i s b ase- o ^ e l inoider.o e found in a random p o p u latio n o. t f . t u . or .even eases for each hunor.u tnou.e.,a o. . . giTen a year expectancy of seventy. * . . vvich is average On t h a t h a s is , T h etfo ra h .r.e s, _ . w.pcv.e # should na vs p o p u la tio n of 15.000 f o r the l a s . te ,, . - ten eases between - twen.y .-v end the actual prevalence fo r ten y e a .., t..i- , itrl, . the actual prevalence is nine cases. ^ In K cntreel, with tne te.. yea. . - w.bs i t h as, as you se e , ,i* ninety or six ninety-tnree eases. . t th<~k I t ls wortnvr-^xe wO e ig h t hundred f if ty - s ix o 1 tu._ - , . * ,,- t r e e l , the ra te since -to. i - t. mention te a t ***- - t rc c - population v a s cr.-j r a t e p e r hundrea e-nousar... * - and in 1950, ,i t* hya.es - wacnec < :a-,V*-*-> ....... In co n clu sio n , t h i s paper h a s n 't te e n , by any means, the in te n tio n to b rin g the fin a l answer to tne pros- le n of the f in a l r e la tio n between the in h a la tio n of asces- to s fib e rs and the development of pulmonary cance., t- * _ th in k th a t th is incomplete study, I must ma.. -c-ve found one of the most r e p re s e n ta tiv e groups of asoestos workers, b eliev in g th a t the data co llected in Tnetfcrc Mines do n o t seer, to in d ic a te a causal r e la tio n s h ip , *r.d th a t i f i t be so, th a t the d ata do not c o rre la te the data of Doctor Kerewether in G reat B r ita in . Thank you. (A p p lau se). p v rtOCTOB RHOADS: Im curious to observe the remark of lo c tc r Car t i e r of the mass survey employed in n is group, =~c ` *e v eei ar.y p a tie n ts v l t h e s rly ciceer. I nust presune th a t tie aass survey vas net s v i c i e r , - y 1 . t e, ,0 i t th is nesns, a f t e r a i l , f e r pU ;:tr.r up a ilseaae v ile: i s tr e a ta b le and lr. many in ste n e e s c u r s t:e , r.sy n et have been su fficien t* In also very curious about tne fifty -th re e autopsied in d iv id u als e f vhec ter. had pulr.orjry eaneer. I thouh t they v ere a u te p s ie d because i t vas t i e u c i t t.'.ey r.s bsve had pulnonary cancer. I t vas not a routine autopsy v,v DOCTOR CABTII?.: No* sc* .jTXvTtrnrarcsdvl^ I O - lE L M.E..M gy pQCTO?, RHOADS! gre th e re any questions on th is p ap e r. 0*c re ep o n ce). Of co u rse , tn. e iin--m ic a .ion iiss c le a r tn a t tnere *s no danger of pulnonary cancer fro<.**.* t.*e vv,cc*r.'iifir*s ir. p &- ** tie -ile r group, and perhaps you are r ig h t. I t appears to * , th a t a s b e s to s is i s a very h ea lth y a iln e r.t as f a r as car. cer i.s concerned, 'uTnhee^.ee seer.s to be no d isc -ssi--.* SY I>0C?OH PLATTE: Ky sin e is P la tte fro r. E irtear, Lake. I t ' s e s s e n t i a l l y a gold n ir.in c d i s t r i c t . We n o , have sr. asbestos^ r.ine in the Town of S a r v ilie near W ils o n . 1 - t as. . , .. i c ; s - i r-ean i t has nothing to the doctor v n a . h is f i r - - * E*1 ^ do v i t h^ cancer - bbunw* vhat ^he looks fo r f o r in d ic a tio n s of tro u b le frcco asb esto s? pv DOCTOR RnOASSt - " " ^ e s t i o r . i s , What are the f i r s t in d ic a tio n s * tro u b le ir o n asb esto s e n s u r e . Can you er.sver th a t. Doctor? t v T>r>r?OR C A R T ISs r ^ T T t th in k th e re i . sr.y s p e c if ic syr.ptor.s ex cept as actu ally changes in the - i f the f.b ro s.s i . ex. l i v e enough, t h a t i s dyspnea and cy anosis, on the extrsne d eg ree, b u t th a t i s , r c r a s b e s to s is , in ny experience, h ev. had about - I can ner.tion, v have n in e ty -e ig h t cases of a sb e sto sis i s our group end only the group vitr. r.ar..ec \ RECEWtP F.HHS.S^=5. "da7E : Z E L L i z b -^ MI.M exposure and many - fo r n**T 7**?s 6:1d x a ^ tia e vaer* they s t a r t to reach f i f t y - f i v e and over, they are more dyspneac, and I think the main th in g , the re sis ta n c e tc i t , they seem to die more ra p id ly once they reach f i f t y , seventy y ears w ith o u t much o f any d is e a s e . V ie .in a few ncntns, they go down the h i l l very ra p id ly . BY DOCTOR RHOADS: What do they die of? BY DQCTO? CAP.TISR: They d ie , some from card iac arc from g e n e r^ -.-e d m iscellaneous d iseases, and i from b ro n ch iectasis, tu t I d o n 't th in k , in my ex p erien ce, th ere i s ar.y specie^ , . c tu re ex cep t t h s t in a few, in two or three aor.ths, they go down very r a p id ly . BY D0CTS3 RHOADS: Doctor Vorwald would lik e to comment. r.v DOCTOR VOg*AID: I 'd lik e to comment ju s t s b i t . We have beer, en couraging Doctor C artier to continue or pursue th is study in the r a th e r is o la te d p o p u latio n in T hetford. We are p reeently conducting a s te lla r epldeniologieai survey in a neighboring c ity . U se engaged in the nteteg of asbestos. Of co u rse, I th in k you r e a liz e Doctor C a r tie r 's e i f . - c --t i e s te a community such ss Ih e tfo rd , where he trust re iy upon the m a te ria l a v a ila b le to h te . and ve d e h st.d hew tee rxit-'.VtO f H,H&S 3 ? j.. ' 1 ,91s Kiu.Iw.M**** incidence of cancer in h is exposed population in Thetfera m ight be i d e n t i f i e d , and we have su g g e ste d , as he d id , r e v iew a l of the c h e st Roentgenograms, of a l l these c a se s, tr.e Roentgenograms having been taken during the l a s t p erico cf f i f t e e n y e a r s . A dm ittedly though, there w i l l be a number o f ca ses o f pulmonary cancer m isses, by tn at netr.od, *e have con sid ered sputum exam ination of a la rg e population such as t h a t , but a t the moment, th e b e s t we car. do was su rvey and study the c h e s t Roentgenograms oj. t n s le r g e se r ie s of individuals exposed to a special industry, SY DOCTOR RHOADSt And you d id n o t p ick up any can cer, I take i t , in so doing? EY DOCTOR CAP.TIER: Oh, y e s , from th e X -ray, EY DOCTOR RHOADS: ' From your survey? BY DOCTOR CARTIER t Yes - no, n o t from mass survey; aul tne ca ses h.v been detected in the c lin ic , BY DOCTOR RHOADS: Im a l i t t l e puzzled about t h i s , Tnis car. De a very in te r e s tin g to p ic . Yon ssy s e t s snrvey didn't do i t tmt the review of Roentgenograms tsi:er. vnen I n o iv ic - .- s applied for medical care? D '-> DOC1^0^ CAP.TIES* the c lin ic . Ho, t h a t 's a ro u tin e exam ination aw EY D O C ^ RHOADS? Bov d. oes th a t rc'liif*fe .r oiiwm- the nass survey? p v DOCTOR CAP.TH3 : . . I think i t d i f f e r s in tn a t t - a P0 ^ 1 or age do not tahe advantage ^ ^ " " ^ ^ i t the c lin ic , a ll the cases have been c e t.c te o at . c l l , i c and a fter that th e , h a t. been f o i l - * P. " " fcave the ea ses o f p o s t n o r te n . ov r.nr^O?, RHOApS t ^ . This in d ic a te s vh at ve have r e fe r r e d to exO* c ,+ tr<* p o in t, th a t senenov the c a s s a number o f d isc u ssio n s a t t r ... P . - tbs actual d etection arc u-e surrey d o esn 't coae through to the actu of the d etection f a c ili t y in hr-r-e-ng ? n ed icel heads always. ^ farther discussion? _ (Ko r e s p o ..s e ). I- - , 1 proceed to the n ett paper. ?cctor -- J0n to o v , i s P ro fesso r o f Pathology and Pear, a t C ollege o f South C arolina. Doctor Lynch. " * - S S S S m ^ -- (Doctor Lynch reac. a . ? - f i l e a t the Saranac L aboratory.) Paper w hich is on . Pv pnrTQR RHOADS: n ^ -erlv ar.i Thanh you, Doctor Lynch, f o r a v er, o. - T1I3' m:HX. P4GE 394 RECEIVED f.H.H&S DATE: J U l 3 1 157S M.E.M ftT DOCTOR RHOADES: Tnask you, Doctor Itfucb, for * ry orderly n i EK. fhGAES: " t-t.VtD f.H.H&S DATE:-JUL 3 i JS7S M.E.M Sou say that the mass survey did so t reveal these cases bit 50V th s t the roentgenograms taken vhen the individuals applied for n e sic a l cere did EE. CAJ.TIHF.: Ho, the roentgenogram vas taker, during a routine culmination at the c lin ic . EE. EHCA2S: Sov does that d iffe r fren the mass survey? CAr.TIIh: I t d iffe r s in that people ever 5C years cf age c.c not taus advantage cf t..e mass rurvey. A ll the cases nrve tee:, retectec at tr.c- c--.me and, la te r , have beer, fo llcv ed up and nave ccne tc. autopsy. Ea. JiJOAIS: I t appears that somehev the mass survey rcesn't alvays res ir. the actual detection cf cancer and in tie bringing cf t ie patient ir.tc xaedical hands.