Document km907MYkpNRw7V5n60JRrKQ1y

a. u. .4. Anuariix cw ixitcsriu.it. hh.ii.tii IJutl concluded that lung .-sneer war a Spe cific industrial hazard o( eertain aibestos workers and that, after 20 years of exposore, the risk U 10 times as great as for the general population. This article it important fur several rea sons. in addition to the definite conclusions at which a arrives. For example, it begins by stating that "in view of the infrequency of ssbesiosis, this large number of cases f61 OKS 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 char asbestos** is an infre quent occurrence. Estimates of the number of persons potentially exposed to asbestos dust .in the United Slates alone rsry front 10.000 to 35.000, and the incidence of asbestosis of any degree might be higher than Doll imagines. This study. Kite so many others, involves autopsy records The number of persons involved in the statistical analysis it only 113, representing only 1.042.25 man-years ol life. It is also true that in selecting men who had been employed for at least 2U years, the study automatically excluded those who died from other causes after shorter employment. Another reason why this publication is of importance is a statement which it con tains to the effect that "the. strongest evi dence that it (lung cancer) may be a hazard fin asbestos workers) has been produced by Mercwcther and by Gloyne." In 1951 ` Gloyne V. presented a. review of 1205 autopsies on persons who had worked in various dusty occupations. This number included 132 asbestos workers, nf whore 121 showed "pneumoconiosis"--pre sumably asbestosis. Primary cancer of the lung.occurred 17 times in this group, an inddcncc rate of 14.1 for hmg Cancer among asbestosis cases coming to aatefty. There were in his scries 796 cases with siii- --#s 6.951 of these also showed pri mary cancer of the lung. The incidence of lung vuncvr in other forms of pneumoconio sis q-a* 6.7$r, and in 169 cases which proved not to hare any type of pneumo coniosis it was 8.35<. Gloyne considered "the mortality of the asbestos wotkers" to 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. Gtoyne's caws were submitted to him for study because the findings were unusual for uncomplicated pneumoconiosis. It can reasonably be assumed that OSes, including those of asbestosis. in which the finding* were not considered unusual were ttnt sent to Dr. Gloyne for examination. As a nut ter of fact, hi the_ same patagrafih in which he expresses concern over the incidence rate in asbestosis. Dr. Gloyne himself Ijoints out that the rate (or lung cancer based on necropsies at (he London Chest Hospital was 2Ufo while the figures of the Registrar-General showed only 2.15c. He thus recognised that autopsies on a cer tain selected group of cases were nut rep resentative of the general population. It would seem. then, that notwithstanding the value nf Dr. Gbiync's work, its importance as an Index ol the prevalence of lung can cer in asbestotics has been misinterpreted by some who have quoted him. A0 that it really shows is the fact that in a group ol 121 cases, selected for special study pri marily because they seemed abiKirnnl by preliminary examination. 17. nr 14.1(7, had hmg cancer. Merewrlhrf ' in 1947. in the nrport ol the Chief Inqjector of Factories, reviewed all eases rc|virted between 1924 and 1946 in which asbestosis was the cause nf death or a coexisting condition. This work was bier extended to include all such cues re ported up to December. 1954. by which time there were 344 deaths, including 205 males and 139 females. Among them were 55 case* (I65t) of cancer of the long. 41 in males and 14 in females. It is tpiite |*wsible that a large number nf sjVsww wto* not not die nf their asbestosis. or in whose 6Jt 4'vf. IT, Jnr. *03* /'"V *.V, -7.-J....1. -