Assessment of treatment related thyroid dysfunction in patients with head and neck cancer

8. SUMMARY: Purpose: To assess, retrospectively and prospectively, thyroid dysfunction in head and neck cancer patients who received external beam radiotherapy; regarding radiotherapy fields and dose, tumor site and other local or systemic treatments and propose a follow-up schedule. Material and Methods: Totally 378 patients are classified into two groups. Patient Group-I including 153 operated laryngeal, 80 nasopharyngeal and 112 oral cavity and oropharyngeal cancer patients were evaluated retrospectively for treatment related thyroid dysfunction through patients data files. Patient Group-ll including 33 head and neck cancer patients analysed prospectively. Thyroid function tests were performed once prior to and once every 3 months after radiotherapy course for this group and thyroid dysfunction was evaluated regarding surgery, radiotherapy and chemotherapy. Results: The median follow-up time for 153 operated laryngeal carcinoma patients was 44 months. Four (% 2.6) patients in this group found to have clinically apparent hypothyroidism. After a 36-months median follow-up time, none of the 80 nasopharyngeal cancer patients showed signs of hypothyroidsm. Clinically apparent hypothroidsm was detected in only 1 (%0.8) of 112 oral cavity-oropharyngeal cancer patients after a follow-up period of 25 months. One patient (%3) in group-ll was found to have thyroid dysfunction after surgery and prior to radiotherapy. At time of analysis, 29 ( %87.8 ) patients were euthyroidic, 2 (%6.1) patients were subclinical^ hypothyroids and 2 (%6.1) patients were clinically apparently hypothyroidic. All patients with thyroid 50dysfunction were locally treated with combined surgery and radiotherapy whereas none of the patients treated with radical radiotherapy had experienced hypothyroidism. Conclusion : Even after a short follow-up period, the possibility of experiencing thyroid dysfunction is found to be %12.2 in head and neck cancer patients which locally treated with combined surgery and radiotherapy. We recommend to perform thyroid function tests for this group of patients once prior to and once every 3-6 months after radiotherapy course. Hypothyroidsm, Radiotherapy, Head and Neck Cancer 51