The recurrence rate of thyroid cancer after surgery is specifically based on the pathological type of thyroid cancer and the degree of lymph node metastasis. Among them, medullary thyroid and undifferentiated thyroid cancer have larger recurrence rates, while papillary thyroid cancer and follicular thyroid cancer have smaller recurrence rates. For papillary thyroid carcinoma, if the cancer is less than 1 cm and there is no lymph node metastasis, the recurrence rate is 2% to 3%. For patients with lymph node metastasis, especially on the right side, the recurrence rate is relatively high, around 20%. On the other hand, the recurrence rate of follicular thyroid carcinoma is relatively low, around 15%, with less lymph node metastasis, and the incidence of hematogenous metastasis is more common than that of papillary carcinoma. Medullary thyroid carcinoma has a recurrence rate of about 40%, mainly due to the presence of lymph node recurrence. Undifferentiated carcinoma of the thyroid has a high recurrence rate, is less likely to undergo surgery, and even if surgery is performed, it basically recurs, with a recurrence rate as high as 90%. Therefore, the recurrence rate of thyroid cancer varies with different pathological types, different prognosis and regression after surgery.