Recent trends in different histological types of lung cancer in Tokyo based on pathological autopsy records

The recently increasing trend of lung cancer mortality in Japan was qualitatively analyzed. As the percentages of cases undergoing pathological autopsies in Tokyo were thirty for males and twenty-six for females during the period from 1979 to 1983, the histologically classified death rates in Tokyo could be estimated by combining the reported cases of death from lung cancer with the proportion of these of known histological type. The results indicated an increase in adenocarcinoma, and a decrease in squamous-cell carcinoma, except for the older age-group of men. The latter result suggested that the results were affected by the decreasing proportion of smokers and by the improvement in cigarette quality. The increase in small-cell and large-cell carcinoma, and the decrease in undifferentiated carcinomas, could be explained by problems associated with differing diagnostic standards. However, when these three different types of carcinoma were considered as a single type, the death rate was shown to be increased except in younger age-groups of women.