Cancer is a systemic disease, surgery and radiotherapy are local treatment, while chemotherapy is systemic treatment. Therefore, postoperative chemotherapy for esophageal cancer and pancreatic cancer, in combination with surgery, can achieve very good curative effect. This chemotherapy is usually administered from two months after the patient is discharged from the hospital, which is the best time. If the time is too short, the patient will recover poorly after surgery and the chemotherapy will be difficult to tolerate, but it is not good. Unless there are clear intraoperative multiple distant lymph node metastases, chemotherapy may also be administered earlier on a case-by-case basis. The number of chemotherapy sessions is generally three to five. The number of chemotherapy is too much for the body to bear. It will be counterproductive.