How long malignant thyroid cancer can live after surgery depends mainly on the period of thyroid cancer detection, pathological type and whether it is metastatic or not. Relatively speaking, the earlier it is detected, the easier it is to treat; papillary and follicular carcinoma have a better prognosis, while the survival time after metastasis is not ideal. 1. Period of detection: for early thyroid cancer patients, early detection, early diagnosis and early treatment generally do not affect the life expectancy of most patients; for mid-stage thyroid cancer patients, the 5-year survival rate is about 70%; for advanced thyroid cancer patients, active treatment can extend the life expectancy by 1-3 2. Pathological type: How long can malignant thyroid cancer live after surgery is closely related to the pathological type of malignant thyroid cancer. Generally speaking, papillary carcinoma and follicular carcinoma have a better prognosis; these two pathological types of thyroid cancer are less than 3 cm in size, and with timely treatment, the 5-year survival rate can reach over 90%; medullary carcinoma and undifferentiated carcinoma are highly malignant and usually have a poor prognosis, especially undifferentiated carcinoma, which has a very low 5-year survival rate of less than 10%, while medullary carcinoma is slightly higher than undifferentiated carcinoma, with a 5-year survival rate of less than 30%; 3. Whether the cancer is metastatic or not: no matter what kind of malignant tumor, metastasis such as organ metastasis or bone metastasis occurs after surgery is a kind of advanced stage, and the effect of treatment is relatively limited. This condition is usually treated with conservative chemotherapy or radiotherapy to try to improve the quality of life of patients, and the survival time is relatively short.