Document LpdnOdx2ORVp7Yzbg2qQ6MO0q

LUNG CANCER IN ASBESTOS MINERS "proved" instances of lung cancer. On the other hand, they cannot, in fairness, be dis regarded completely. It is for this reason that mortality rates have been calculated both ways. Table 8 gives the rates by age groups. The rates by length of employment are shown in Table 9. During the first 40 years of 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" cases reported for a total of 240 men dur ing the six years, or about 1440 man-years of exposure. When the "suspected" cases are added, one case does show up in this Table 8---Lung Cancer Deaths by Age Groups Table 9.--Lung Cancer Deaths by Length of Employment Number of Persons and Number of Lung Cancer Deaths Length of Employment No. of Persons No, of Deaths Proved Total 6-9 ............................ 10-19............................ 20-29............................ 30-39............................ 40-49............................ M+.............................. 1.796 2,398 922 603 186 66 0 1 3 5 0 0 0 l 3 7 \ 0 Totals............ 5,S 9 12 Annual Lung Cancer Death Rates per 100,000 Man-Years of Exposure Length or Employment Proved Total 6-9......................................... ............. 10-19....................................... ............. 20-JS....................................... 30-39....................................... M9....................................... w+......................................... 0 7 0 7 64 193 90 0 Over-all................... 34 Number of Persons and Number of Lung Cancer Deaths Age Group No. of Persons No. of Deaths Proved Total 20-44............................ 46-54............................ 56-64......... .................. 65+.............................. Unknown................... 3,901 1,124 615 31S 3 1 l 3 4 0 1 3 3 5 0 Totals______ 6,958 9 12 Annual Cancer Death Rates per 100,000 [an-Years of Exposure Age group Proved Total aw4...................................... 45-i4........... .......................... 55-64...................................... ............ 66+....................................... Unknown........ ................... ............ 81 0 4 44 31 236 0 Over-all................. ............. 26 34 period. This would produce a rate of 69 per 100,000, again demonstrating the im portance of these questionable, but. un proved, cases to the final conclusion, because, if there were no cases in this number of men with long exposure, and if asbestos is a carcinogenic agent, it must be concluded that these 240 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 of this age group had died earlier of lung cancer. Table 18, which appears later in this section, in- 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 being a carcinogenic agent, for, if 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 be found. The only possible error in this interpretation could occur if the weighted exposures were inversely related to years of employment, Table 10.--Lung Cancer Deaths by Exposure Category Number of Persons and Number of Lung Cancer Deaths No, of Deaths Category Persons Proved Total 1............................ 11............................ Til.............................. Unknown................... 2.031 2,150 1,772 5 4 3 2 0 4 4 4 0 Totals............ 6.958 9 12 Annual Lung Cancer Death Rates per 100,000 Man-Years of Exposure Eicposure Category proved Tota I........... II........... Ill........... Unknown., 33 33 23 31 19 37 00 Over-all 26 34 Braun--Triton 643 SPNY 000302