If the cancer is in early stage, the tumor cells have been completely removed through radical surgical treatment, and the patient does not need chemotherapy after surgical treatment. However, if lymphatic metastasis or metastasis to peripheral organs occurs in the middle or late stage, even after surgery, the risk of recurrence is still relatively high. For patients with high risk of recurrence after surgery, chemotherapy is still needed after surgery. In another case, if the intramucosal cancer belongs to malignant tumors with relatively low differentiation and high malignancy, it is still advocated to carry out prophylactic chemotherapy after surgery to prevent tumor recurrence and reduce the chance of tumor recurrence.