[Epidemiological studies on thyroid cancer in Nagasaki City]

We studied 89 cases of thyroid cancer registered at the Nagasaki Tumor Registry during the period from 1973--1977. The incidence of thyroid cancer tended to be higher in persons exposed to the atomic bomb, especially women, than in the nonexposed population. Compared with nonexposed individuals, the relative risk for thyroid cancer was increased in distally as well as proximally exposed persons, but not in early entrants to the bombed city. In 83 histologically examined patients, papillary carcinomas were highly predominant, they were more prevalent in the exposed than in the nonexposed population.