Cancer in ex-asbestos cement workers in Israel, 1953-1992

A cohort of 3,057 male workers employed in an asbestos-cement plant using 90% chrysotile-10% crocidolite, located in Northern Israel, was followed from 1953-1992 for incidence and mortality from cancer. In the years 1978-1992, the cohort had an elevated risk for all malignant neoplasms combined (n = 153, SIR = 117, ns), lung cancer (n = 28, SIR = 135, ns), mesothelioma (n = 21; SIR > 5000, p < .0001), unspecified pleural cancer (n = 5; SIR = 278, P < .0001), and liver cancer (n = 7, SIR 290, ns). Risks for colo-rectal (n = 19; SIR = 79, ns), bladder (n = 12, SIR 69) and renal cancers (n = 5, SIR 104) were less than expected. Risk for mesothelioma showed a sharp risk gradient with duration of exposure, increasing from 1 per 625 for those employed less than 2 years to 1 per 4.5 workers employed over 30 years. The ratio of mesothelioma to excess lung cancer cases was 2.9 to 1, or 3.6 to 1, if pleural cases of unspecified origin were included; the pleura to peritoneum ratio of verified mesothelioma cases was 20 to 1. This atypically high ratio of mesothelioma to excess lung cancer cases is suggested to be the combined result of high past asbestos exposures in the workers and their low prior risk for lung cancer, and possibly, relatively early smoking cessation in relation to asbestos exposure.