[Epidemiological studies of colon cancer in Nagasaki City with special reference to radiation exposure].

Epidemiological studies were conducted on 223 cases of colon cancer registered at the Nagasaki Tumor Registry from 1973 to 1977, with particular emphasis on the relation to radiation exposure. The incidence in atomic bomb survivors was not significantly different as compared with nonexposed persons. By site, cancer of the sigmoid colon was more frequent in males than in females, especially in older people, but no difference was seen by exposure status. Histologically, about 90% was relatively differentiated adenocarcinoma and showed no difference by age, sex or exposure status.