Document ym7YXDxQq3KOe927beLR4ZqGV

128 RONSKET ET Ah. ~Vd, 28 incidence of cancer in a number of the other organs" (Cramer, 1936). A constant watch must be kept on `'amounts1' of cancer if proportions are being altered by industrial forms of the disease. OCCUPATIONAL CANCER IN THE DYESTUJTS INDUSTRY Why should 1 in 10 or even more of men engaged in the manufacture and usage of certain dye intermediates (aromatic amines) develop tumors of the bladder? These workers are exposed by inhalation, ingestion and absorption of these compounds through the skin and yet tho tumors arc located in the bladder. This striking observation has fired the imagination of many workers and we think we are justified in stating that we are beginning to understand the reasons. Tho knowledge thus gained has altered our conception of the range and mode of action of chemical carcinogens in an interesting way. An extremely good survey of tumors of the urinary bladder in workmen en gaged in the manufacture and use of certain dyestuff intermediates in the British chemical industry has recently been published by Case and his associates* (Table 2). They have shown that although there is a small spontaneous incidence of bladder tumors in tho general population (2)*j times greater in males than in females and rare under 55 years of age) the risk is 30 times greater in chemical workers and the age of onset is on an average 15 years earlier. Manufacturers, users and purifiers are affected in descending order of severity, the noxious sub stances being 2-naphthylamine, benzidine and possibly auramine and magenta. There is no evidence that aniline 1b incriminated. As the induction period is constant at 15 to 20 years, the age at onset of the disease is dependent upon the ago at entry of a man into the industry. This is finked with the fact that it is the length and not the severity of exposure that matters, individual susceptibility being a marked feature. There is no special tendency for industrial tumore to be TABLE 2 Occurrence op Bladder Tumobs in Manufacturers and Users op Dyestupp Intermediates (Case bt al.*) Population at Risk = 4522 Men Expected deaths in comparable general population Actual deaths in industry Actual cases in industry Risk in industry Chemical exposure Ago of onset Induction period Degree of molignanoy Survival after diagnosis Exposure Individual susceptibility 3-5 127 202 30 times that of general population Bensidiue Beta .naplithylaminc Alpha-naphUiylamine 15 years earlier than in general population 15-20 years Comparable to tumors of bladder in general papulation 20 pur cent survived 10 years Length, not severity, affects induction time A marked feature of unknown cause Peb-li more c per cei of the In 1 reduce traced engage 1950, r fruit ir Men any tin use. C bladde drawn records It is pi certain bladdei and it t isomers volatile search and it: mediati strayed Of gr the loca tion of naphth: develop individi If 2-nap Iffedtc If benzi sonal cc tumors mice, he vation) must bo original tion of tl A atuc a cower the caps these sut