Hypothyroidism following definite radiotherapy in patients with head and neck cancer; prospective observational study

Head and neck cancers are one of the common cancers seen in state of Himachal Pradesh. The treatment consists of surgery and radiotherapy with or without chemotherapy. Definitive radiotherapy for head and neck cancer results in radiation of exposed part of Thyroid gland. The reported prevalence of incident hypothyroidism varies from17 to 47%9. The variability of radiation induced hypothyroidism could be related to varied dose of radiation, volume of thyroid gland exposed, ethnicity, geographical conditions related to iodine contend of the soil, endemicity of hypothyroidism, autoimmune status of the individuals. Development of hypothyroidism carries the risk of  poor wound healing and recovery. Therefore determining the radiation induced hypothyroidism and it’s risk determinants in our patient population is of great importance in developing informed protocols for screening and early detection of high risk patients of head and neck cancers following definitive radiotherapy to reduce morbidity.The contemporary data on radiation induced hypothyroidism and risk factors in patients with head and neck cancers undergoing definitive radiotherapy is limited to develop evidence based screening protocol for detection of radiation induced hypothyroidism.Thus we propose to determine the incidence of hypothyroidism and its risk factors among patients of head and neck cancer undergoing definitive radiotherapy free of hypothyroidism at baseline in prospective observational study. The findings of the study would help in developing evidence based protocol for screening high risk patients for radiation induced hypothyroidism using the limited resources rationally.