Whether colorectal cancer patients need adjuvant chemotherapy after surgery still depends on the clinical stage of the tumor. Stage I: Adjuvant chemotherapy is not required after surgery. Stage II: The need for adjuvant chemotherapy after surgery is controversial, but studies have shown that patients with stage II colorectal cancer with the following high-risk factors may benefit from chemotherapy: 1. T4 stage tumor; 2. poor histologic grading (grade 3/4 lesions); 3. lymphovascular/vascular infiltration; 4. nerve invasion; 5. bowel obstruction; 6. local perforation; 7. positive or indeterminate surgical margins; 8. cleared lymph nodes Insufficient number (<12). Stage III: Postoperative adjuvant chemotherapy is required. The chemotherapy regimen depends on the specific condition. Stage IV: Palliative chemotherapy to control the tumor and prolong life.