Hypothyroidism after Radiotherapy of Locally Advanced Head and Neck Cancer / 대한방사선종양학회지

ABSTRACT

PURPOSE: The aim of the present study was to retrospectively evaluate the incidence of hypothyroidism in locally advanced head and neck cancer patients who received radiotherapy (RT) either with or without neck dissection. MATERIALS AND METHODS: From January 2000 to December 2005, 115 patients with locally advanced head and neck cancer and who received definitive RT or postoperative RT including standard anterior low-neck field were recruited to be part of this study. Nineteen patients had undergone ipsilateral neck dissection, whereas, 18 patients underwent bilateral neck dissection, and 78 patients were received RT alone. Patients' ages ranged from 28 to 85 years (median, 59 years) and there were a total of 73 male and 42 female patients. The primary tumor sites were the oral cavity, oropharynx, hypopharynx, larynx, and other sites in 18, 40, 28, 22 and 7 patients, respectively. Radiation dose to the thyroid gland ranged from 44 Gy to 66 Gy with a median dose of 50 Gy. Follow-up time ranged from 2 to 91 months, with a median of 29 months. RESULTS: The 1- and 3-year incidence of hypothyroidism was 28.7% (33 patients) and 33.0% (38 patients), respectively. The median time to detection of hypothyroidism was 8.5 months (range, 0 to 36 months). A univariate analysis revealed that neck node dissection was a risk factor for hypothyroidism (p=0.037). However, no factor was statistically significant from the results of a multivariate analysis. CONCLUSION: Patients treated for advanced head and neck cancer with radiotherapy with or without neck dissection will develop hypothyroidism. It is important to check the thyroid function periodically in these patientsespecially with the risk factor of neck node dissection.