1.Patients with a postoperative diagnosis of stage I do not require any chemotherapy. 2.Stage II patients, if there are no high-risk factors, usually do not need chemotherapy. At most, fluorouracil-based drugs alone should be administered orally. What are the high-risk factors? They include poor differentiation (hypofractionated, indolent cell carcinoma, mucinous adenocarcinoma, etc.), vascular/lymphatic infiltration, perineural infiltration, T4 (penetrating the whole intestinal wall), intestinal obstruction, intestinal perforation, positive cut margins, and less than 12 lymph nodes sent for examination. 3, Stage II patients with the above high-risk factors may be considered for chemotherapy with fluorouracil alone or with oxaliplatin chemotherapy, or observation-based chemotherapy without chemotherapy. Which ones do not need chemotherapy although they are high-risk? For stage II colon cancer, it is recommended to check dMMR (mismatch repair protein deletion). dMMR is a sign of good prognosis. Even if the tumor is poorly differentiated with high-risk factors, as long as dMMR is present, the prognosis will be good and will not benefit from chemotherapy, so chemotherapy is not needed. 4.Stage III, chemotherapy is generally needed, and oxaliplatin-containing regimens, such as FOLFOX regimen, are preferred. 5. It is especially noted that colon cancer is relatively insensitive to chemotherapy, no matter which stage, the benefit of chemotherapy is not much and needs to be cautious. For example, for stage II patients, only 3-5% of those who benefit from chemotherapy! For stage III patients, the benefit of chemotherapy is only about 10%! More than 90% of patients are ineffective chemotherapy, which does more harm than good.