Hypothalamic, pituitary and thyroid dysfunction after radiotherapy to the head and neck.

One hundred-ten patients who had nasopharyngeal cancer and paranasal sinus tumors and were free of the primary disease were studied one to 26 years following radiotherapy. There were 70 males and 40 females ranging in age from 4 to 75 years, with a mean age of 36.5 years. During therapy both the hypothalamus and the anterior pituitary gland were in the field of irradiation. The radiation dose to the hypothalamus and the anterior pituitary gland was estimated to be 400 to 7500 rad with a median dose of 5618 rad to the anterior pituitary gland and a median dose of 5000 rad to the hypothalamus. We found evidence of endocrine deficiencies in 91 of the 110 patients studied. Seventy-six patients showed evidence of one or more hypothalamic lesions and 43 patients showed evidence of primary pituitary deficiency. Forty of the 66 patients who received radiotherapy to the neck for treatment or prevention of lymph node metastasis showed evidence of primary hypothyroidism. The range of the dose to the thyroid area was 3000 to 8800 rad with a median of 5000 rad. One young adult woman who developed galactorrhea and amenorrhea 2 years following radiotherapy showed a high serum prolactin level, but had normal anterior pituitary function and sella turcica. She regained her menses and had a normal pregnancy and delivery following bromocriptine therapy. These results indicate that endocrine deficiencies after radiotherapy for tumors of the head and neck are common and should be detected early and treated. Long-term follow-up of these patients is indicated since complications may appear after the completion of radiotherapy.