I. Need for regular follow-up after liver cancer surgery Liver cancer is a malignant tumor with biological characteristics of recurrence and metastasis. Therefore, there is still a risk of recurrence after surgical resection of liver cancer. If regular follow-up can be conducted to detect recurrence and metastasis at an early stage, reoperation on recurrence and metastasis can still achieve better curative effect. According to domestic data, the recurrence rates of liver cancer 1, 3 and 5 years after radical surgery are 17.1%, 32.5% and 61.5%. It means that within 5 years after hepatectomy, more than half of the patients with hepatocellular carcinoma recur, and after recurrence, they can also undergo surgical resection, and the 5-year survival rate of reoperated patients can reach 40.8%. Therefore, even if recurrence of hepatocellular carcinoma occurs after resection, if re-excision can be performed, the survival period can still be significantly prolonged. However, the basis of re-excision is early detection of recurrence, and the method of early detection of recurrence is regular follow-up. Regular follow-up after resection of hepatocellular carcinoma can be done by fetoprotein, ultrasound and chest X-ray. If the positive preoperative methemoglobin drops to normal after surgical resection of hepatocellular carcinoma and then rises again later, without chronic active liver disease or other explanations, it indicates recurrence. Ultrasound has the advantages of being sensitive, convenient and inexpensive, which is an important tool for liver cancer recurrence monitoring. In some patients, recurrence may be preceded by lung recurrence, so chest X-ray is needed to monitor whether there are recurrent foci in the chest. If B-ultrasound is not completely clear, CT examination should be performed in time. If metastases from other parts are still suspected, whole-body isotope scan should be performed. Generally, methotrexate and ultrasound should be checked every 3 months and chest X-ray every 6 months for 5 years after surgery, which can be increased appropriately in the first year; after 5 years, the risk of recurrence decreases and methotrexate and ultrasound can be performed every 6 months. The postoperative follow-up of liver cancer is lifelong follow-up. Clinically, we have encountered recurrence more than 20 years after surgery, which is worthy of your attention. Second, follow-up of high-risk group of liver cancer We define those who have a history of hepatitis or positive marker of hepatitis B virus or positive antibody of hepatitis C virus, and those who are over 35 years old as high-risk group of liver cancer, and those who have family history have higher risk of liver cancer. However, this does not mean that high-risk groups will definitely develop liver cancer. Among the high-risk group, the number of people who develop liver cancer is still very small. Usually, regular check-ups of methemoglobin and ultrasound are needed every six months, and if possible, follow-up visits should be made to a large hospital with more experience so as not to miss the time of early diagnosis and treatment. Follow-up of high-risk groups is an important tool for early diagnosis of liver cancer. The five-year survival rate of early liver cancer after surgical treatment can reach 70%-80%.