Autopsy cases of asbestosis in Japan: A statistical analysis on registeredcases

There are 525 (484 male, 38 female, 3 unknown) autopsy cases with asbestosi s registered in the Annual of the Pathological Autopsy Cases in Japan, whic h is issued by the Japanese Society of Pathology for the years 1958-1996. T he 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% 1223/225,801) for 1990-1996. There was a significant incre ase in asbestosis cases across the three time periods (p <.0001). The numbe r of asbestosis cases increased markedly among individuals who worked with asbestos products, as well as among those employed in asbestos-processing f actories. The frequency of malignant tumors associated with asbestosis was 61.0% (320/525), acid the frequency also increased across the three time pe riods, from 43.4% (33/76) to 62.8% (142/226) and 65.0% (145/223), respectiv ely. 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.