Salivary gland tumors in atomic bomb survivors, hiroshima, japan. II. Pathologic study and supplementary epidemiologic observations.

A pathological investigation was undertaken in Hiroshima on cases seen between 1945 and 1971 to determine the relationship between salivary gland tumors and exposure to atomic (A) bomb radiation. Of the 208 cases of histologically confirmed salivary gland tumors, 62 were A-bomb survivors and 146 were nonexposed. The relative risk based on the rate in the nonexposed for malignant tumors of salivary glands among the exposed in Hiroshima Prefecture was 11.0, while that of the submaxillary gland was 13.8 and that of the parotid gland was 9.8. They were all highly significant by X2 test (P less than 0.001). The latent period of malignant salivary gland tumors was shorter in the exposed than in the nonexposed. Four cases of benign salivary gland tumor, all being benign mixed tumors of the parotid gland, were observed in children whose parents had been exposed. The incidence of mixed tumors of the salivary gland among the exposed in Hiroshima City was 2.0 times higher than that among the nonexposed and showed a tendency to increase with proximity to the hypocenter (P less than 0.01).