In normal work, we will meet many colorectal cancer patients and their families, and they will ask this question: Doctor, do we need chemotherapy after surgery? So what kind of patients need chemotherapy after surgery? In fact, the postoperative treatment plan depends entirely on the patient’s pathology. According to the pathological results of surgery, colorectal cancer can be divided into stage I, stage II, stage III and stage IV according to the TNM staging, and in general, the five-year survival rate of stage I patients is often over 90%, and gradually decreases with the increase of stage. Therefore, stage I colorectal cancer patients do not need chemotherapy, while stage II patients decide whether they need chemotherapy according to the presence or absence of pathological high-risk factors, which mainly include: 1, T4 stage; 2, poor histological grading (grade 3/4 lesions); 3, lymphovascular/vascular infiltration; 4, nerve invasion; 5, intestinal obstruction; 6, local perforation; 7, positive or indeterminate surgical margins; 8, the number of cleared Insufficient number of lymph nodes (<12). In contrast, postoperative adjuvant chemotherapy is required for stage III patients, and the chemotherapy regimen depends on the specific condition. However, for patients with IV, the purpose of chemotherapy is only to control the progression of the tumor and prolong the life of the patient. The duration of adjuvant chemotherapy for colorectal cancer after radical surgery is mostly about six months, and the specific chemotherapy regimen should be individualized by the doctor according to the condition. Therefore, as long as the treatment plan is followed, most colorectal cancer patients' tumors can be cured. Of course, each patient should decide whether to undergo chemotherapy or not according to his or her condition, and should communicate with professional doctors to develop a more standardized and individualized treatment plan so that patients can benefit from it.