Thyroid Cancer Occurring as a Late Consequence of Head-and-Neck Irradiation: Evaluation of 1056 Patients

From January 1 to September 30, 1974, we examined 1056 of 5266 subjects (20.1 per cent) who had received therapeutic irradiation primarily for infections and inflammatory disease of the upper respiratory tract at our institution during the 1940's and 1950's. The tonsillar and nasopharyngeal region was the treatment site in 85 per cent of those examined. Palpable nodular thyroid disease was found in 16.5 per cent, and nonpalpable lesions were detected by ^99mTc pertechnetate thyroid imaging in an additional 10.7 per cent, for a prevalence of nodular disease of 27.2 per cent. Operation on 71 per cent with nodular disease revealed thyroid cancer in 33 per cent (60 of 182). Preliminary analysis for potential risk factors suggests a correlation between radiation exposure and the presence of thyroid nodules (P<0.001). These findings indicate that nodular thyroid disease, both benign and malignant, continues as a major health problem for at least 35 years in exposed subjects. (N Engl J Med 294:1019–1025, 1976) Thymic enlargement in infancy treated with external irradiation was reported in 1907.¹ Not long thereafter the use of external irradiation was proposed for treatment of enlarged tonsils and adenoid tissue in children.² For most of the next four decades such therapy was administered to numerous infants with a normal or enlarged thymus and to children with chronic inflammatory disease of the upper respiratory tract. In 1950, Duffy and Fitzgerald³ reported that nine of a series of 28 children with thyroid carcinoma had received prior irradiation for thymic enlargement and raised the possibility that the irradiation was an etiologic factor in.