Colonoscopy will not say on the spot that it is cancer, this is only to assist in diagnosis, the real diagnosis needs to rely on pathological examination. In the process of colonoscopy, occupying lesions may be found in the intestinal cavity, and the morphology and structure are not very optimistic from the naked eye, and cancer is highly suspected. If surface erosion, irregular nodular growths or ulcers are found during colonoscopy, tissue biopsy will be taken and sent to pathology for examination, and the final result will be based on pathology. If the endoscopist has a high suspicion of colon cancer during the examination, but the pathology taken does not confirm the diagnosis of cancer, do not be careless. Because there are certain errors in taking biopsy specimens, deeper tumor sites or contaminated specimens, etc., which may affect the examination results. Pay attention to review after treatment in a short period of time. The symptoms of colon cancer are not obvious in the early stage, but in the late stage, it is easy to show changes in bowel habits, emaciation, anemia, low fever, etc. Especially, those who have family history of colon cancer and colon polyps must follow up regularly, pay attention to reasonable diet and eat more fresh vegetables to avoid insufficient intake of fiber tissue and too single diet variety.