Who are at high risk for colorectal cancer The following people are at high risk for colorectal cancer: positive fecal occult blood, history of colorectal cancer in first-degree relatives, previous history of intestinal adenoma, personal history of cancer, change in bowel habits, any two of the following (chronic diarrhea, chronic constipation, mucus and blood stools, history of chronic appendicitis or appendectomy, history of chronic cholecystitis or cholecystectomy, long-term mental depression, etc.) ). High-risk groups should pay attention to regular medical checkups and seek timely medical consultation when abnormalities are detected, such as abdominal discomfort, change in bowel habits, blood in stool, abdominal mass, black stool and anemia. The most reliable method to detect colorectal cancer: colonoscopy The most reliable method to detect colorectal cancer at an early stage is colonoscopy. Before colonoscopy, the examinee needs to take “bowel cleanser” to make the fecal matter in the intestinal cavity expelled so as not to obscure the lesion. For suspected small mucosal changes, the lumpector will use electronic staining endoscopy and magnification endoscopy to further observe the mucosal glandular duct openings and capillary flow, and ultrasound colonoscopy can also clarify the depth of lesion invasion and lymphatic metastasis. What are the early symptoms of colorectal cancer? Colorectal cancer is a common malignant tumor, including colon cancer and rectal cancer. The occurrence of colorectal cancer is related to high fat and low fiber diet, chronic inflammation of colon, colorectal adenoma, genetic factors and other factors such as: schistosomiasis, pelvic radiation, environmental factors (such as lack of molybdenum in soil), smoking, etc. Colorectal cancer has no symptoms in early stage or the symptoms are not obvious, only feeling discomfort, indigestion, occult blood in stool, etc. With the development of cancer, symptoms gradually appear, which are manifested as change of stool habit, abdominal pain, blood in stool, abdominal mass, intestinal obstruction, etc., with or without systemic symptoms such as anemia, fever and emaciation. Tumor may cause changes in affected organs due to metastasis and infiltration. Colorectal cancer shows different clinical symptoms and signs depending on its location.