Whether the thyroid cancer recurs 42 years after surgery is related to many factors, such as the type of thyroid cancer pathology, whether the surgery is timely and proper, and the effect of treatment, etc. If the surgery is not thorough or the postoperative medication cannot be adhered to and the low iodine diet can be controlled, it will easily lead to the recurrence of thyroid cancer after surgery. Most of the patients with papillary thyroid cancer can greatly reduce the probability of recurrence after thorough surgical treatment and postoperative medication, together with regular review. Thyroid cancer, especially differentiated thyroid cancer (DTC), has a good prognosis, low mortality rate and long survival period, but it is still necessary to follow up and observe the post-surgery thyroid cancer patients on a regular basis, which mainly includes blood testing of relevant indexes, as well as regular ultrasonography of the thyroid gland. Monitoring of post-surgery thyroid cancer patients in order to detect recurrent tumor and metastasis at an early stage, so as to achieve early detection and early treatment, which can reduce the harm brought by the disease and improve the survival rate of patients.