Early symptoms of colorectal cancer 1. Middle-aged and elderly people with unexplained loss of appetite, weakness and emaciation should do the relevant screening and follow-up work to facilitate early detection and diagnosis. 2.Unexplained progressive anemia, pale face day by day, and other parts of blood loss and blood diseases have been excluded. 3.Unexplained change of stool habit, change of stool habit refers to abnormal defecation feeling, incomplete defecation, alternating hard and rotten stool, more frequent stool, anal urgency, deformation of stool, etc., which is one of the early manifestation symptoms of colorectal cancer. 4. Abdominal pain, discomfort or hidden pain in the abdomen at the beginning of the disease, which is related to defecation. When there is paroxysmal abdominal pain, it is because the tumor has narrowed the intestinal cavity and obstructed the passage of feces, which is mostly seen in the middle and late stage patients. 5, blood in the stool or bloody mucus stool, where the stool with dark red blood and bloody mucus stool and continue to appear, gradually increasing, with diagnostic value; fecal occult blood test repeatedly positive, with screening value, do not be treated as “hemorrhoids”, “colitis” bleeding, etc. This is a common case of clinical misdiagnosis and mistreatment, which is a profound lesson. High-risk groups of colorectal cancer 1, family history of colorectal cancer, colorectal cancer refers to malignant tumors of the colon, rectum and anus, which is an autosomal dominant disease, caused by mismatch repair gene defects in the human body, especially if both parents suffer from this disease. It is reported that about 1/8 of familial cancer members or their offspring have colorectal cancer. 2.History of familial polyps of the colon, polyps mostly develop in adolescence and can become cancerous after the age of 40. Therefore, once patients are diagnosed with colorectal polyps, they should undergo total colon and rectal resection as soon as possible to prevent cancerous changes. 3, adenomatous polyp patients, adenomatous polyps of the colon more than 1cm, there is a 40-50% chance of cancer, should be timely excision treatment to interrupt the polyp malignant transformation. 4.Patients with colorectal cancer, reproduce abnormal abdomen or defecation after surgery, positive carcinoembryonic antigen, should promptly do e-colonoscopy to exclude the existence of multiple primary cancers of the colon or recurrence of intestinal cancer. 5.Patients who have suffered from gastrointestinal tumors (such as gastric cancer), breast cancer, etc., which are homologous to the etiology of colorectal cancer.