1. Institute of Cancer and Basic Medical (ICBM), Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China.
2. Department of Radiation Oncology, Cancer Hospital of University of Chinese Academy of Sciences, Hangzhou, Zhejiang 310022, China.
3. Department of Radiation Oncology, Zhejiang Cancer Hospital, Hangzhou, Zhejiang 310022, China.
4. The First Clinical Medical College, Guangdong Medical University, Zhanjiang, Guangdong 524000, China.
5. Medical Research Institute, Hangzhou YITU Healthcare Technology Co., Ltd, Hangzhou, Zhejiang 330106, China.
6. Shanghai Key Laboratory of Artificial Intelligence for Medical Image and Knowledge Graph, Shanghai 200050, China.
7. Department of Oncology, the Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong 524001, China.
This paper reviews the factors related to hypothyroidism after radiotherapy in patients with head and neck cancer to facilitate the prevention of radiation-induced hypothyroidism and reduce its incidence. Hypothyroidism is a common complication after radiotherapy in patients with head and neck cancer, wherein the higher the radiation dose to the thyroid and pituitary gland, the higher the incidence of hypothyroidism. With prolonged follow-up time, the incidence of hypothyroidism gradually increases. Intensity modulated radiotherapy should limit the dose to the thyroid, which would reduce the incidence of hypothyroidism. In addition, the risk factors for hypothyroidism include small thyroid volume size, female sex, and previous neck surgery. The incidence of radiation-induced hypothyroidism in head and neck cancer is related to the radiation dose, radiotherapy technique, thyroid volume, sex, and age. A prospective, large sample and long-term follow-up study should be carried out to establish a model of normal tissue complications that are likely to be related to radiation-induced hypothyroidism.
Keywords: Head and Neck Cancer, Hypothyroidism, Radiotherapy