Cancer in asbestos-mining and other areas of Quebec.

Employing incidence data from the Quebec Tumor Registry, we examined the relative risks of cancer of all sites for the years 1969-73 in the asbestos-mining, rural, and metropolitan counties of Quebec Province, Canada. Generally, rates for males exceeded those for females, and the relative risks in the asbestos-mining counties for 7-10 different sites of cancer, all of low incidence, were from 1.50 to 8.08 times those of other rural counties of the Province for both sexes. Metropolitan counties exhibited equally high risk for many of these sites. We discovered higher risks among males in asbestos-mining counties for cancer of the pleura, peritoneum, lip, tongue, salivary gland, mouth, and small intestine and higher risks among females for cancer of the pleura, lip, kidney, salivary gland, and for melanoma. Because of the likelihood of a long latent period for asbestos-related cancers, the risks we observed were possibly the product of since-altered occupational and environmental conditions existing 20-30 years ago in the asbestos-mining areas. The similarities in risks for most cancers in asbestos-mining and urban areas were noteworthy.