Document B4rn3MQ5BRYDp04E93Y06mmL

Vol.$5 p Intermediates; T\unor Jder carcinoma ider carcinoma known known tatuma dder papilloma toma, acoustic gland ircinoipa, intestinal lrcinoma ddet papilloma v known log was found to have a he liberation of free 2^feese factors has led i^ronds produce their excretion because they i, coupled with certain UoyBon, 1953)." m s in (1) asbestos textile esented here are, as yet, d to Hueper's thorough iated with aabestoais, 33 8 cases with coexistence ? Workers > (MJS) began to collect ts, and it will be remempeculiar bodies and tbe in the sputum (Stewart, ill and Haddow, 1932*"). persons who hod worked is fibers. In 8 persons no small numbers of bodies ition is thus 72,46 males Feb. l$SS OCCUPATIONAL CANCER 131 TABLE 4 Incidence o* Cancisa in Asbestos Textile Wobkebs at Postmobtbm Examination compOlric.ated Tuherculoafs end LuagCUKcr and rctitoncii Cancer and Aahwlosia Asbcctails AAetnll Acbestonis Number of coses investigated postmortem (72) Inoideuce of lung cancer (per cent) Average age at death Average age at starting work Avorage period of exposure (years) Total Prior to 1331 In oases entering after 1031 MF 23 18 54(21)f 31(21) 23(21) 14(10) 5(2) MP 12* 3 47(12) 28(12) KP 12* 2 26.1 8.7 56(11) 27(10) 1802) 14(7) 7(5) 26(10) 12(10) MF 13 * One man bod asbeBtosis, tuberculosis and lung cancer. f Figures in parentheses represent the number of coses for which the information was available. and 26 females. In Table 4 the data in regard to the association of asbeatosis and cancer arc given. Cancer arising primarily in pleurae, lungs or bronchi was present in 26.1 per cent of males and 8.7 per cent of females. This-significantly higher incidence in males may be accounted for by the fact that 7 women died before the cancer age, 4 following parturition or abortion and 3 from tuber culosis. There was no significant difference in average age at death, average period of exposure or average age of starting work between males with uncomplicated asbeatosis and those with the complication of lung cancer. This is interesting, as in the dyestuff industry death was accelerated by the supervention of bladder cancer. It was noted that the degreo of fibrosis was rather leas in the lungs with cauccr than in those without. Tuberculosis significantly lowered the age at death. A fair assessment of the period of exposure is difficult in such a series of eases. Taking into account the known fact that efteT a carcinogen has ceased to be applied to a tissue a latent period is required before the development of the malignant change, it was decided to use the period from the first entry into the factory until death as the period of exposure. This disregards absences from the factory for any reason. It also presupposes that once the fibers have gained access to tho lung the carcinogenic process is sot in motion, becoming fully developed at the end of the latent period. Two interesting features deserve mention. The morbid anatomy and histology of the 13 lung cancers of which full notes were available was unusually varied. Four were large tumors situated near tho lung hilum, disseminating in char acteristic fashion and of adcnocaroinomatous or oat-cell type. Seven wore situated in the periphery of the lung, usually near the base, 3 disseminating by blood and lymph streams and the other 4 remaining confined to the lung substance. Six of these were adenocarcinomatous or of oat-coll type, I being spindle cell and possibly a rhabdomyosarcoma. Small peripheral cancers were described by Raeburn and Spencer (1953)u as the likely precursors of the large hilar masses