Thyroid function in pediatric patients after neck irradiation for Hodgkin disease.

Thyroid function was evaluated in a consecutively treated group of children and adolescents with Hodgkin disease who received incidental radiation to the thyroid gland. Ten of 27 (36.7%) were found to have elevated concentrations of thyroid-stimulating hormone (TSH). Two groups of patients had an increased incidence of thyroid dysfunction - those who had not had a pretreatment lymphangiogram and those who were less than 13 years of age at the time of neck irradiation. The estimated percentage of patients who did not have a pretreatment lymphangiogram who will develop TSH elevation was 67.7% and of patients who were 13 years of age or less when irradiated, 64.8%. Thyroid dysfunction developed in 6/7 patients who had both of these risk factors present.