Asbestos and cancer in the Sennan District of Osaka

The cancer incidence among asbestos workers in the Sennan District and its surrounding of Osaka Prefecture, Japan, and the results of a mass survey in the above area since 1957 were evaluated from view points of epidemiology. During the period from 1953 to 1979, 107 patients with asbestosis were admitted to this Hospital. Twenty-six (24%) of them died of various carcinoma; 21 had lung cancer, 2 pleural mesothelioma and 3 had stomach cancer. Respiratory insufficiency due to pulmonary asbestosis was responsible for 41 deaths (38%). by a cohort survey of the 297 asbestos workers in the same district, 4 cases of lung cancer, and 3 cases of gastric cancer were detected and cases of cohort survey were followed up for 19 years. Fifty-seven (10%) of 556 cases of silicosis and 14 (11%) of 125 cases of pneumoconiosis other than silicosis or asbestosis were found to have lung cancer, but no mesothelioma. These results indicate that lung cancer and mesothelioma are associated more frequently with asbestosis than with non-asbestos pneumoconiosis (p less than 0.001 as tested by chi2-test). The standardized mortality ratio of lung and stomach cancer among the inhabitants of the Sennan District was calculated based on the statistics during the period of 10 years (1968-1977). the ratio of observed death to expected death of both cancers was smaller than 1.1, and there was no significant increase of death of lung and stomach cancer, although the risk of lung cancer tended to increase among male inhabitants. Discussions were made on the problems related to asbestos industry.