Most thyroid cancers metastasize to the lymph nodes in the neck first, while a few metastasize to distant tissues or organs, such as bones and lungs, through blood flow. In general, papillary, follicular, medullary and undifferentiated carcinomas account for most of the metastases, and once metastasis occurs, lymphatic metastasis usually occurs at an early stage. Then the metastasis will first metastasize to the lymph nodes around the neck. Therefore, radical thyroid cancer resection with lymph node dissection in the neck can usually achieve the goal of radical cure.