1. Medical history and physical examination, every 3-6 months for 2 years, then every 6 months for a total of 5 years, and annually after 5 years. 2.Monitoring of CEA, CA19-9 every 3-6 months for 2 years, then every 6 months for a total of 5 years, and annually after 5 years. 3. Abdominal/pelvic ultrasound every 3-6 months for 2 years, then every 6 months for a total of 5 years, and annually after 5 years. Chest X-ray every 6 months for 2 years, and then once a year after 2 years. 4.Thoracoabdominal/pelvic CT or MRI once a year. 5.Colonoscopy within 1 year after surgery, if there is any abnormality, review within 1 year; if no polyp is seen, review within 3 years; then once in 5 years, any large intestinal adenoma that appears in the follow-up examination is recommended to be removed. If preoperative colonoscopy is not completed for the whole colon, it is recommended to perform colonoscopy 3-6 months after surgery. 6.PET-CT is not a routinely recommended examination.