After the first treatment, colorectal tumor patients often tend to neglect regular review, which is very unfavorable to the consolidation of treatment effect and timely detection of relevant problems. In addition to the aspects of clinical education work that must be strengthened, the lack of attention of patients and family members is quite an important aspect. Clinically, we can see a lot of such cases. The biological characteristics of malignant tumors that are prone to recurrence and metastasis determine the objective requirement of lifelong follow-up examination for tumor patients, and adhering to standardized postoperative observation and review is also a very important part of the tumor treatment process. For patients with colorectal tumor, there are several roles: 1. to evaluate and deal with side effects, because surgery of gastrointestinal malignant tumor usually needs to change the original structure of gastrointestinal tract in the reconstruction of gastrointestinal tract, so patients may have gastrointestinal symptoms such as abdominal distension, diarrhea, abdominal pain and even some systemic symptoms after surgery; some patients need to perform adjuvant therapy such as radiotherapy, chemotherapy and immunotherapy because of their condition after surgery, and these treatments may be accompanied by mild or moderate symptoms. These treatments may be accompanied by mild or severe complications. Therefore, a timely and comprehensive assessment of the patient’s postoperative recovery status is needed, and timely symptomatic treatment is required, and patients need to be reviewed regularly. 2. Early detection of lesions and treatment of patients with progressive and certain early gastrointestinal malignancies, despite radical surgery, some patients still have recurrence and metastasis after surgery. And regular postoperative comprehensive review and follow-up can help patients detect new lesions in time and effectively improve survival rate. 3. Receive guidance to avoid doubts Many patients with gastrointestinal malignant tumors will have changes in their living habits after surgery and have various doubts. Compared with various sources, the guidance obtained from regular hospitals and doctors is more informative and more in line with the principle of individualized treatment. The time of follow-up review Postoperative recurrence of colorectal malignant tumor patients mostly occurs in the first 1-3 years after surgery, so the number of review should be relatively frequent in the first 3 years after surgery, and the interval of review can be relatively extended after 3 years. The specific follow-up time and content vary slightly according to the type of disease. The timing is generally arranged as follows: once a month within six months after surgery; within 3 years after surgery, follow up once every 3 months; 4-5 years: once every six months; after 5 years, once a year. Examination content Ask for medical history, new abdominal pain, change in bowel habit, rapid weight loss and other symptoms should be alert; blood test: blood routine, liver and kidney function, GI tumor markers (CEA, etc.); imaging: abdominal and pelvic ultrasound, chest X-ray, further review CT or PET-CT if there are abnormalities, to clarify whether there are other organs or lymph node metastasis; colonoscopy: clarify the healing of anastomosis Patients who cannot undergo total colonoscopy due to tumor obstruction before surgery should have a follow-up colonoscopy 3 months after surgery to exclude other lesions; patients with prophylactic fistula should have a follow-up colonoscopy 3 months after surgery or after chemotherapy; in other cases, the colonoscopy should be repeated once a year after surgery.