1.Stage T1N0, T2N0 rectal cancer with negative cut margin after surgery, no chemotherapy is needed. 2.T3N0 lower segment (tumor is 5-7cm from the anal verge), or any T,N1-2 rectal cancer, or positive cut margin, chemotherapy and radiotherapy are recommended after surgery. 3. For T3N0 upper rectal cancer, if the cut margin is negative, with good prognostic features, the benefit of radiotherapy is very limited, and chemotherapy alone can be considered. Good prognostic features include: negative cut margins, 12 lymph nodes for examination, and no vascular invasion. 4.For T4N0 and locally unresectable rectal cancer, preoperative chemoradiotherapy can be used, followed by review, surgical resection if possible, and postoperative chemotherapy. 5.The TN stage, cut margin and lymph nodes of the tumor are stated in the pathology report after surgery.