National cancer mortality and incidence in Japan.

In Japan cancer mortality statistics have been prepared by site, sex, and age group since 1937. The trends in age-adjusted death rates for selected sites from 1937 to 1975 in intervals of two or three years, and the age-adjusted death rates for some sites by prefecture in 1968-1972 were summarized. Concerning the accuracy of cancer mortality statistics, special consideration should be given to senility in Japan. In 1975 deaths due to senility accounted for 4.3% of all deaths for all ages. Though the regional cancer registration was being operated in 16 prefectures in Japan as of 1976, the incidence rates were published for only six prefectures. The percentage of cases registered from death certificate only in six registries in Japan was compared with that in the registries in the United States, indicating that the completeness of registration was yet unsatisfactory in Japan. As an index of accuracy of diagnosis, the percentage of cases confirmed histologically was also compared.