Thyroid dysfunction in children receiving neck irradiation for Hodgkin's disease.

Thyroid function was studied in 46 long-term survivors of pediatric Hodgkin's disease with a median follow-up time of 10.5 years. The mean age of the patients at the time of treatment was 8 years. Treatment consisted of radiotherapy alone in seven patients and combined radiation and chemotherapy in 39 patients. The radiotherapy dose to the thyroid gland was less than 2000 cGy in one, 2000-2500 cGy in 15, 2500-3000 cGy in 17, and greater than 3000 cGy in 13 patients. Evaluation consisted of clinical examination and thyroid function tests of total and free triiodothyronine, thyroxin, arid thyroid stimulating hormone levels. Twenty-one of 46 patients (45.6%) showed thyroid function abnormalities, however only nine of them had diffuse or nodular hyperplasia on physical examination. Risk factors of age, chemotherapy schema, total radiation dose, and dose per fraction did not significantly influence the incidence of thyroid dysfunction.