Radiation-induced tumors of the head and neck following childhood irradiation. Prospective studies.

Nodules were found in 1108 subjects who received childhood radiation for benign conditions of the cervical area at our institution. This is 37.5% of 2958 subjects, out of a total of 5379, for whom there is follow-up information. Of the 848 subjects who have had thyroidectomies, 297 (35.0%) had thyroid cancer. In addition to thyroid tumors, salivary, neural, and probably parathyroid tumors also occurred as a late consequence of childhood radiation. Prospective studies of the subjects indicate that thyroid nodules are continuing to occur at a constant rate. The measurement of serum thyroglobulin is helpful in identifying individuals for whom the risk of developing a nodule is increased. Follow-up of patients with nonsurgically-treated nodules indicates that some of their nodules are progressive. At the present time there is no indication that radiation-induced cancers behave differently than ones in other settings. However, some of their characteristics, especially their multicentricity and occurrence in younger individuals, indicate that continued follow-up is necessary. On the basis of the data generated by the follow-up program at our institution and programs elsewhere, recommendations for screening, treatment, and follow-up are made. The recommendations stress the importance of estimating risk based on radiation dose, previous tumors, and serum thyroglobulin, in arriving at clinical decisions for these subjects.