Postoperative adjuvant chemotherapy is required for patients with high-risk factors for stage II colon cancer. Risk factors for stage II colon cancer include the following: 1. postoperative pathology suggests undifferentiated or hypodifferentiated tumor 2. tumor with vascular infiltration (including blood vessels or lymphatic vessels) 3. preoperative intestinal obstruction 4. pathological biopsy of less than 12 lymph nodes 5. perineural infiltration 6. local tumor perforation 7. tumor margin adjacent to tumor tissue or tumor margin uncertainty or margin Definitely positive.