There is a possibility of recurrence 40 years after thyroid cancer surgery, and patients should have regular review. Thyroid cancer is a kind of malignant tumor disease, which usually has no specific symptoms in the early stage of the disease, and some patients will have symptoms such as poor swallowing, hoarse voice and choking cough. Patients can be treated by surgery, and some patients can achieve the effect of clinical cure; however, this disease has the possibility of recurrence, and there is also the possibility of recurrence 40 years after surgery. If partial resection is chosen for thyroid cancer surgery, the residual thyroid tissue still has the possibility of malignant transformation; if total metronidazole excision is chosen, iodine 131 treatment is usually also carried out after the surgery in order to reduce the recurrence. However, 40 years after the surgical treatment of thyroid cancer, it is generally considered that the original thyroid cancer has been cured and the chance of recurrence is very low. After surgery, thyroid cancer patients should undergo regular review as prescribed by the doctor. At the same time, they should exercise appropriately, enhance nutrition, maintain a calm mind, avoid staying up late and overworking, etc.; try to avoid being in a chemical environment or a more polluted environment, so as to avoid recurrence of the disease as much as possible. After thyroid cancer surgery, patients should have regular checkups, and have timely diagnosis and treatment for any physical discomfort.