Cancer incidence of A-bomb survivors in Nagasaki City, 1973 - 1982

Subjects were residents older than 30 years ascertained through the population-based cancer registry in Nagasaki City during a ten-year period from 1973 to 1982. The total number of cancer patients was 6,243 (3,456 men and 2,787 women), 2,626 of whom were A-bomb survivors. Stomach cancer was the most common, irrespective of sex, in both exposed and non-exposed groups. Crude incidence of cancer of any organ was higher in the exposed group, especially the group of people entering the city early after the bombing, than the non-exposed group. In the groups exposed at <2,000 m and at 2,000 - 10,000 m from the hypocenter, the incidence of stomach, lung, and thyroid cancers and malignant lymphoma; and the incidence of stomach, breast, and thyroid cancers were radiation-dose dependent in men and women, respectively. Age-adjusted relative risks of breast and thyroid cancers were significantly higher in the exposed group of women than the non-exposed group. Comparing cancer incidence during the first and latter five years, the incidence of thyroid cancer and malignant lymphoma tended to decrease or remain unchanged in both men and women. The incidence of colorectal cancer showed a tendency to increase. An increased incidence of stomach and lung cancers was restricted to the exposed group of women. As for breast cancer, the exposed group of women had a tendency for decrease, as opposed to the non-exposed group with the increased incidence. There was no significant difference in histologic types between the exposed and non-exposed groups. (Namekawa, K.)