Neoplasia in Children Treated with X-rays in Infancy for Thymic Enlargement
X-ray treatment of enlarged thymus in infants is no longer commonplace but is still practiced. The incidence of neoplastic diseases in 1,400 infants so treated between 1926 and 1951 was determined and compared with the incidence of neoplastic disease in 1,795 of their untreated siblings and with the expected incidence in the general population as calculated from vital statistics. Even taking limitations of the study into consideration the findings indicate that the radiation therapy of the thymus applied in infancy must be suspected as the cause for the greater incidence of neoplastic disease observed in the x-ray treated group; the majority of neoplasms occurred in those known to have received more than 200 r. Six individuals in the x-ray treated group developed cancer of the thyroid, none of the untreated siblings were so afflicted compared to the expected incidence, as calculated from data on the general population, of 0.08.
