INTRODUCTION: This study aims to analyze the incidence of hypothyroidism (HT) in patients who underwent radiotherapy (RT) for head and neck cancers (HNC), and to determine risk factors.
METHODS: This study was a retrospective analysis of patients who were treated with RT alone or in combination with surgery and/or chemotherapy between January 2005 and May 2012. Patients were grouped according to the primary tumor site, TNM staging system, age, gender, total radiation dose (TRD), mean radiation dose of thyroid gland (MRT), neck dissection, and chemotherapy.
RESULTS: A total of 90 patients who were treated with RT were analyzed. The median age was 52±13 (range, 12-87) years. The histopathologic finding of 88 patients was squamous cell carcinoma, others were adenocystic carcinoma and undifferentiated carcinoma. The median follow-up of all patients after RT was 15 (range, 6-72) months. Post-radiotherapy HT was found in 31 patients (34.4%). In this group, clinical and subclinical HT was present in eight (26%) and 23 (74%) patients, respectively. Age younger than 60 years and increased MRT (especially mean thyroid dose 20 Gy<) were significant risk factors for post-radiotherapy HT (p<0.05).
DISCUSSION AND CONCLUSION: Physicians should pay more attention to HT in patients who were treated with RT for HNC during follow-up.