[Epidemiological studies on multiple primary malignant tumors in Nagasaki City]

Ninety-four cases of multiple primary malignant tumors registered at the Nagasaki Tumor Registry during the period from 1973-1977 were studied. The crude incidence rate tended to be higher in atomic bomb survivors although the difference was not significant. The male:female ratio was 1:1.19. Cases in the sixth decade of life were dominant, the average age was somewhat lower in females than in males. Stomach cancer was observed in 48 patients (51.1%; triple malignancies in 8 cases (8.5%).