Malignant tumors in people exposed as children to atomic bomb in Nagasaki

In order to determine both the conditions under which malignant tumors occurred and the pathological specificity of those tumors in people exposed as children (at the age of 0-9) to the atomic bomb in Nagasaki, a comparative study was made of malignant tumors (including brain tumor but excluding leukemia) in 88 exposed cases taken from the data of the committee for the statistical analysis of tumors in Nagasaki and from other literature, and in unexposed cases of malignancy. The following items were analyzed; the distance from the bombed area (doses), the age at the time that the disease occurred, the latent period, the annual incidence of disease, the site of tumor, and the type of tissue. The results are summarized as follows, although they are inconclusive because of the small number of cases. The incidence of malignant lymphoma, cancer of the tyroid gland, brain tumor, sarcoma, and cancer of the ovary had a tendency to be higher in the exposed cases than in the unexposed cases. From the standpoint of sex, there was a tendency that cancer of the stomach and malignant lymphoma occurred more often in females than in males. On the other hand, sarcoma and brain tumor were seen more often in males. From the standpoint of the relationships among these factors: the distance from the bombed area, the latent period, and the type of tumor, it was suggested that cancer of the thyroid gland, brain tumor and cancer of the stomach were observed especially in cases which had been exposed as children. In addition, it was considered that the influence of not only a short distance from the bombed area but also a middle distance from that area can not be neglected. (Namekawa, K.)