Thyroid Dysfunction following Radiotherapy and Combined Therapy in Non-Thyroid Head and Neck Cancers

INTRODUCTION: In patients with head and neck cancers thyroid gland bears the brunt in terms of either excision or irradiation resulting in loss of functionality of the gland leading to thyroid dysfunction. The purpose of this study was to evaluate thyroid function following radiotherapy and combined therapy in non-thyroid head and neck cancers. MATERIALS AND METHODS: It was a prospective study of 51 patients with head and neck cancers for duration of one year. Thyroid function tests were done before and at the end, 3 months and 6 months following treatment. RESULTS: Out of 51 patients, 47 (92.15 %) were males and 4 (7.8 %) were females. All the patients received radiation to the neck to a dose of > 50 GY. 36 patients received concurrent chemotherapy and 7 patients underwent surgery. 4 patients were found to have clinical hypothyroidism, 16 patients subclinical hypothyroidism, 1 patient clinical hyperthyroidism and 1 patient subclinical hyperthyroidism. Thus a total of 22 patients developed thyroid dysfunction (P value of 0.001). CONCLUSION: Recognizing thyroid dysfunction early and treating it prevents thyroid dysfunction related complications. Hence, thyroid function tests should be done routinely during follow-up in head and neck cancer patients receiving radiotherapy.