Neoplasms in Man after Irradiation in Infancy

Abstract

In this paper, we present the results of the third follow-up survey of a series of approximately 3,000 persons treated with X-rays in infancy for thymic enlargement. This epidemiologic study of the relationship between radiation exposure and the subsequent development of neoplastic disease has been conducted at the University of Rochester School of Medicine and Dentistry during the past 12 years (Simpson et al. 1955; Simpson and Hempelmann, 1957; Pifer et al. 1963; Toyooka et al. 1963 a, b). The names of the irradiated subjects were abstracted from the records of all hospitals and radiologists’ offices in Rochester, New York; X-ray treatments were given during the period, 1926–1957. During this time, it was common medical practice in the United States to treat infants with X-rays for enlargement of the thymus gland. The majority of the subjects were irradiated during the first six months of life — many, a few days after birth. The data on tumor incidence in this irradiated population was collected in 1963 by mail questionnaire sent to the subjects, or to their parents. Eighty-four per cent of the total group responded to the questionnaire. All indications of neoplastic disease or other serious illness were verified by consulting medical records. Histological sections of all excised tumors were reviewed, when possible, by one of the University pathologists (Roger Terry, M. D.).

Supported in part, by a grant from the National Institutes of Health (RH 00210).