The choice of colonoscopy should be made on a case-by-case basis.
For example, young patients under 40 years of age can be observed with regular follow-up when there is no wasting, pus and blood in the stool and a negative routine stool test; patients over 40 years of age with long-term chronic diarrhoea, especially if there is weight loss, significant abdominal mass or pressure pain, blood in the stool or a positive occult blood test in the stool, should routinely undergo colonoscopy.