Salivary gland tumors in atomic bomb survivors, Hiroshima, Japan. I. Epidemiologic observations.

An epidemiologic investigation was undertaken in Hiroshima to study the relationship of salivary gland tumors to exposure to ionizing radiation. Two hundred and eleven cases examined between 1953-1971 were confirmed by a review of histologic specimens. Of these, 66 cases occurred in residents of Hiroshima City who were born before the A-bomb: 30 among A-bomb-exposed, and 36 in non-exposed individuals. The incidence of salivary gland tumors among the exposed individuals was significantly higher, 2.6 times greater than that among the nonexposed individuals for all tumors, and 10 times greater for malignant tumors. The incidence increased with proximity to the hypocenter for the directly exposed. An increased incidence was also found among early entrants, particularly those entering the city within 3 days of the A-bomb.