Follow-up interval: The follow-up period after thyroid cancer surgery should start from the month of surgery, every three months within two years after surgery, every six months within three to five years, and every year after five years, with lifelong follow-up. Content of follow-up: Self-examination: monthly self-touching of the neck for enlarged lymph nodes, lumps, etc., checking pronunciation, and timely consultation if abnormalities are found. Specialist examination: check the lymph nodes in the neck and corresponding areas. Ultrasound: ultrasound of the neck: to know whether there is thyroid recurrence or lymph node metastasis in the neck, CT of the neck if necessary; abdominal organs (kidney, adrenal gland, liver and spleen); gynecological ultrasound (uterus, ovaries) for women Chest X-ray (once a year), chest CT, brain MRI if the doctor thinks necessary at follow-up. bone ECT scan (once every two years), unless bone metastasis is suspected (e.g. persistent aggravation of bone pain that cannot be Bone ECT scan (every two years), unless bone metastases are suspected (e.g., persistent worsening bone pain that cannot be explained by common disease), timely ECT or MR, and PETCT when available. Blood tests: serum T3, T4, TSH: to assess the effect of endocrine therapy; serum thyroglobulin (HTg): after total thyroidectomy, dynamic monitoring of serum thyroglobulin can predict early recurrence and metastasis. Follow-up medication: levothyroxine tablets (Euthyroxine) are commonly used clinically. The starting dose of levothyroxine tablets is 50 μg/d morning dose, and the dosage of thyroxine tablets is adjusted according to the TSH level, gradually increasing the dosage to control the TSH value at 0.05-0.1 mU/L is preferred, and the patient is between normal and mild hyperthyroidism. Maintain this dose for life.