Document ppvbv5vDDbBEaRejbje0wYXLB

02/13/2003 THU 10:46 FAX 312 996 1899 UIC LHS CHICAGO V61.26 in this series tumors were loarcinoroaa, sale and 3 in cs. All these mod in any 1 epithelium but without rking under th which to 'idence here ninern must the exposed lust be exntbestos dust enormously hose severe i possibly a and this disease bem examiars and in land mains >e. The difsignificant lers having dned much content of iwaver, an .as greater lbered. All We Incidence 85 2 85 2 Feb. 1965 OCCUPATIONAL CANCfiB 133 TABLE 5 Mineral Content, Duration op Occupation and Pulmonary Fibbosib in Iron-Ore Miners Number to Avtljsc Aft Croup II Petth Average Duration of Occupation (Yews) Avenue Per. centageMineral Conigal to Dry Ling Silica Iron Decree ot Ftbzosb Bronohial carcinoma Fibrosis alone Fibrosis and tuberculosis No fibrosis and no tuberculosis 15 59 75 26 61 32 (11) 1.11 6.3 + 60 34 (20) 1.15 6.3 +++ 57 28 (48) 1-H 5.4 ++ 62 26 (19) 0.59 4.04 0 Figures in parentheses represent the number of eases in which the information was available. The common factor in these 2 types of occupational lung cancer is silica, and it is suggested that this may be the caroinogtmic agent. The presence of silica, (os silicic add) causes pulmonary fibrosis, which precedes the initiation of the malig nant process. The fibrosis is usually of lesser degree, however, in those lungs in which cancer supervenes. On published evidence the case for an etiologic re lationship between nodular silioosis per se and lung cancer is much loss strong than in silicosis associated with siderosis and in asbestosis. Hueper (1952)* examined the literature very thoroughly and came to the conclusion that "the available evidence supporting a causal relation between silicosis and cancer of the lung is unimpressive.*' It seems possible, therefore, that the fibrous nature of asbestos or the presence of hematite dust may exert a modifying effect on the chemical action of the silica or on the fibrotic process itself. Furthor study of the nature of the carcinogenic process in pneumoconioses is thus obviously needed. 6UMMABY The value to the cancer problem as a whole of die study of occupational cancer in the field and by experiment, together with the time lag between these 2 aspects, is discussed. A short consideration of the total amount of cancer in any population follows, and a classification of the types of recognized occupa tional cancer. More detailed consideration of industrial bladder and lung cancer follows. In regard to the former, the extent of the hazard, the nature of the chemicals involved and their metabolism in various species are discussed. In regard to the Litter, the occurrence of lung cancer in a group of 72 male and female asbestos textile workers and in 192 hematite miners in Cumberland, England, is de scribed. REFERENCES 1. Bonser, 6. M., Claybon, D- B., and Jull, J. W.: Ad experimental inquiry inln Iho Ranee of industrial bladder cancer. Lancet. 2:286-287,1951. 2. Bonser, G. M., Claybon, D. JS-, Jull, J. W., and Pybah, L. N.: The carcinogenic properties of 2-amino-l -naphthol hydrochloride and its parent amine 2-naplithyIamine. Brit. J. Cancer, 6: 412-424, 1952. @009