Endocrine complications after radiotherapy for tumors of the head and neck

One hundred sixty-six patients 6 to 80 years of age with nasopharyngeal cancer and paranasal sinus tumors who were free of the primary disease were studied from 1 to 26 years after radiotherapy. Studies in 65 of these patients were performed prospectively. Both the hypothalamus and the anterior pituitary gland were in the field of irradiation. The median radiation dose was estimated to be 5700 rad to the anterior pituitary gland and 5000 rad to the hypothalamus. We found evidence of endocrine deficiencies in 134 of the 166 patients observed. One hundred eleven patients showed evidence suggestive of hypothalamic lesions and 67 patients showed evidence of primary pituitary deficiency. Forty-eight of the 110 patients who received radiotherapy to the neck for treatment or prevention of lymph node metastasis showed evidence of primary hypothyroidism. The median dose to the thyroid area was 5000 rad. Adolescents younger than 15 years of age had a higher incidence of growth hormone deficiency soon after radiotherapy, but the older group showed adrenocortical and luteinizing hormone deficiency. These results indicate that endocrine deficiencies after radiotherapy for tumors of the head and neck are common. The highest incidence of complications occurred 1 to 5 years after radiotherapy, but long-term follow-up is indicated because complications may appear years after radiotherapy.