High-risk group for colon cancer: If the patient has had colonoscopy before and has been diagnosed with colon adenoma; if the patient’s immediate family member has had colon cancer, i.e. positive family history of colon cancer; if the patient has a history of inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease. No matter which of these three is satisfied, they are defined as high-risk group for colon cancer and should have colonoscopy in time. In addition, the high-risk age group for colon cancer is currently considered by the industry to be the age group of 50-74 years old. However, in recent years, it has been reported in the literature that the incidence of colon cancer tends to be early, that is, the incidence tends to increase even below the age of 50.