Mesothelioma mortality in asbestos workers: implications for models of carcinogenesis and risk assessment

Abstract

Mesothelioma death rates in asbestos workers appear to be proportional to the 3rd or 4th power of time from first exposure under a wide range of conditions of exposure for both pleural and peritoneal tumours, though the peritoneal:pleural ratio depends on fibre dimension and type. Age at first exposure has little or no influence, however, which supports the "multi-stage" model of carcinogenesis under which the increase in most cancer incidence rates with age is due to a constant incidence of genetic or epigenetic accidents, rather than to progressive generalized changes in regulatory or immune function. These relationships provide a simple basis for risk assessment, and support the suggestion that mesotheliomas may constitute a high proportion of cancer deaths resulting from early exposure to asbestos.