Cancer developed after irradiation therapy for malignant tumors

Two hundred and sixty cases of double cancers were extracted from 13,000 cases autopsied in Nagasaki University Hospital and its affiliated hospitals between 1958 and 1981. The following criteria for radiation-induced cancer were used: (1) the first cancer was treated with radiation therapy, (2) the second cancer developed at the irradiated field or at the site close to it, and (3) the second cancer was detected or its symptoms occurred 5 years or later after radiation therapy. Seven of the 260 cases were suspected of having developed radiation-induced cancer, of which two A-bomb victims were included. All seven cases were females. In the 7 cases, the first cancer was cervical cancer in 5, thyroid cancer in one, and lymphosarcoma of the neck in one; the second cancer was carcinoma in 4, sarcoma in 2, and leukemia in one. The latent period of cancer ranged from 5 to 23 years with the average of 13.3 years. Histological changes attributable to radiation therapy were observed. One hundred of the 260 cases extracted were A-bomb victims, of which 15 had undergone radiation therapy. It seemed necessary to consider radiation doses used in the treatment of cancer, when surveying health and life span of A-bomb survivors. (Namekawa, K.)