Autopsy Cases of Asbestosis in Japan: A Statistical Analysis on Registered Cases

There are 525 (484 male, 38 female, 3 unknown) autopsy cases with asbestosis registered in the Annual of the Pathological Autopsy Cases in Japan, which is issued by the Japanese Society of Pathology for the years 1958-1996. The frequency of asbestosis (number of cases/total autopsy cases) was 0.017% (76/440,334) for the 1958-1979 time period, 0.058% (226/390,124) for 1980-1989, and 0.099% (223/225,801) for 1990-1996. There was a significant increase in asbestosis cases across the three time periods (p < .0001). The number of asbestosis cases increased markedly among individuals who worked with asbestos products, as well as among those employed in asbestos-processing factories. The frequency of malignant tumors associated with asbestosis was 61.0% (320/525), and the frequency also increased across the three time periods, from 43.4% (33/76) to 62.8% (142/226) and 65.0% (145/223), respectively. Among the 525 cases with asbestosis, there were 174 lung cancers (33.1%), 73 malignant mesotheliomas (13.9%), 29 stomach cancers (5.5%), 14 liver cancers (2.7%), 9 prostatic cancers (1.7%), 8 malignant lymphomas (1.5%), 6 laryngeal cancers (1.1%), 4 pancreas cancers (0.8%), 3 rectal cancers (0.6%), and 28 other cancers (5.3%). The frequencies of lung cancer, malignant mesothelioma, and laryngeal cancer were significantly higher in the cases with asbestosis than among the nonasbestosis cases. The number of malignant tumors related to asbestos exposure is expected to increase in the future.