Hypothyroidism after treatment for nonthyroid head and neck cancer.

OBJECTIVES To determine the incidence of posttreatment hypothyroidism in patients treated with surgery with or without radiotherapy for advanced-stage nonthyroid head and neck cancer and to make recommendations for its detection. DESIGN A prospective study to assess the incidence and time frame of occurrence of hypothyroidism in patients by primary tumor site and treatment modality. Thyroid function tests were performed preoperatively, at the first postoperative visit, and then approximately every 6 months. Patients were followed up for up to 3 years. SETTING Arthur G. James Cancer Hospital and Research Institute, Columbus, Ohio. PATIENTS A total of 251 patients with nonthyroid head and neck cancer were originally enrolled; 198 patients with evaluable data were studied to determine the incidence of posttreatment hypothyroidism. Approximately 80% of the patients had advanced stage (III or IV) or recurrent cancer. RESULTS The overall incidence of posttreatment hypothyroidism was 15% in 198 patients followed up for a mean of approximately 12 months. Hypothyroidism developed in 12% of patients treated with nonlaryngeal surgery and radiotherapy. The group undergoing total laryngectomy (with thyroid lobectomy) and radiotherapy had a 61% incidence of hypothyroidism. The average time to detection of hypothyroidism was 8.2 months. CONCLUSIONS Approximately 15% of patients treated for advanced head and neck cancer with surgery and radiotherapy will develop hypothyroidism. Those treated with total laryngectomy and radiotherapy are at greatest risk.