Document 2jbMyEeKX9MrXNmXxzY4X3d5a

VI. SUMMARY AMO CONCLUSIONS Interest in the question of whether there may be an as sociation between lung cancer and asbestosis or exposure to asbes tos has been evident since the report in 1935 by Lynch and Smith of a case in which lung cancer and asbestosis were both present. As additional cases in which the two diseases coexisted were reported, a causal association appears to have been gradually accepted by many authors, although a few workers considered the correlation to be in conclusive. Cases of lung cancer which had occurred among the as bestos miners in Quebec had been carefully recorded over the years, and the present study was commissioned in an effort to determine whether a causal relationship did, in fact, exist between exposure to asbestos and cancer of the lung. Reference to the Literature shows a remarkable uniformity both of method and of conclusions. In general, the method has been to study a circumscribed series of cases of asbestosis and to enumerate those in which lung cancer occurred. The series may consist of cases coming to autopsy or of death certificates mentioning asbestosis, and the total number has served as the denominator by which the number of lung-cancer cases is divided to produce a certain "incidence rate". This rate, as reported by various authors has been consistently high, and its uniformity is indicated by the following tabulation.