There is still a risk of recurrence after thyroid cancer surgery, especially if the thyroid cancer is locally advanced at the time of surgery or has already developed lymph node metastasis in the neck. In this case, even after radical surgery to remove thyroid cancer and systemic lymph node dissection, there is still a risk of recurrence after surgery. Of course, advanced thyroid cancer refers to the case of distant metastasis, such as lung metastasis, bone metastasis, liver metastasis, brain metastasis and so on. In this case, thyroid cancer is mainly treated with conservative internal medicine, or called anti-tumor angiogenesis therapy. For early stage thyroid cancer, if there is no residual or lymph node metastasis after surgery, postoperative adjuvant therapy is mainly endocrine therapy with thyroxine supplementation and replacement therapy. The adjuvant treatment after thyroid cancer surgery should also depend on the specific pathological type, the degree of tumor load, and the degree of surgical clearance.