Postoperative bowel cancer is usually a disease more sensitive to chemotherapy, commonly colon cancer and rectal cancer. Patients with colorectal cancer, whether they need postoperative radiotherapy should be treated differently, as follows: 1. For early stage patients, generally after radical surgery, the tumor is cut more satisfactorily and the lymph nodes are cleared more thoroughly, radiotherapy is not needed, as long as close follow-up and regular review are done; 2. However, in China, most colorectal cancer patients are found to be actually in the progressive stage, and the patients are already in advanced stage, such patients generally However, in China, most of the colorectal cancer patients are actually found to be in the progressive stage, and the patients are already in the advanced stage, so such patients usually have to do radiotherapy after surgery, because radiotherapy inhibits and kills the residual cancer cells in the blood and lymphatic system after surgery, and with the emergence of various chemotherapy drugs, immunotherapy, including targeted drugs, has a very obvious effect on tumor inhibition. Therefore, postoperative radiotherapy is actually beneficial to patients in clinical practice.