Cancer patients do not always need to undergo chemotherapy after surgery. Whether to put chemotherapy after surgery needs to be decided according to the patient’s condition and the comprehensive assessment of the patient’s whole body. 1. stage of malignant tumor: early stage of malignant tumor, generally chemotherapy is not routinely administered after surgery, if the tumor is found early, the tumor is small, and there is no metastasis, then chemotherapy is not needed after surgery. 2. patient condition: patients who If the patient is old, weak and cannot tolerate chemotherapy or is unwilling to do chemotherapy, they can also not do chemotherapy, they can adjuvant immunotherapy or targeted drug therapy to prevent recurrence after surgery, and at the same time pay attention to regular review to detect metastasis in other parts in time for early treatment. However, some tumors, such as breast cancer, lung cancer, colorectal cancer, etc., have poor prognostic factors, such as hypofractionated carcinoma, with vascular cancer embolism, etc. In order to reduce the chance of tumor recurrence and metastasis, chemotherapy is needed early after surgery or even before surgery, and if necessary, it needs to be combined with radiotherapy and immunotherapy for comprehensive treatment. In addition, some tumors, such as kidney cancer, are not very bright to chemotherapy, so even if these patients have already had surgery, chemotherapy is usually not needed, and postoperative immunotherapy can be used to prolong patients’ survival time.