1. Prevention and care (1) Appropriately reduce the fat and meat content of the diet and increase fresh vegetables and fruits. (2) Colorectal adenomas should be regularly reviewed and removed in a timely manner. (3) For chronic inflammatory diseases of the colorectum, especially long-term chronic ulcerative colorectitis, be alert to the occurrence of cancer and have regular rectal finger diagnosis, X-ray or fiber fine intestinal microscopy. (4) For patients over 50 years old, examination of fecal occult blood twice a year can help to detect colon cancer with less obvious symptoms earlier. 2.Post-operative follow-up (1)Follow up every 3 months for 2 years after surgery, especially the first follow-up should be done in 3 months after surgery. Each follow-up should include medical history and detailed physical examination, blood CEA and other tumor markers, immune function status, blood routine, liver function measurement, fecal occult blood test, chest X-ray and ultrasound scan of liver, peritoneal lymph nodes and pelvis. (2) Fiberoptic colonoscopy should be performed once a year to detect heterochronic polygenic neoplasia and anastomotic recurrence, and a barium enema can be added in between. If for some reason fiberoptic colonoscopy and barium enema are not performed before surgery, one of them should be performed 6 months after surgery. CT or MRI once a year, and the first CT and colonoscopy should be reviewed within six months. (3) Follow-up 2 years to 5 years after surgery can be extended to once every 6 months. Patients who are more than 5 years postoperative can be examined once a year or combined with health checkup plus key items. (4) For patients receiving adjuvant chemotherapy after surgery, CEA and liver function can be increased to once every 1-2 years. Abnormalities found during follow-up should be examined in detail for early detection of recurrent and metastatic lesions. Blood counts should be checked more routinely, at least once a week in patients with DPD enzyme deficiency or on drugs with significant bone marrow suppression.