As people’s health awareness increases, many middle-aged and elderly people have regular medical checkups, including blood tests, abdominal ultrasound, chest X-ray, etc., but few people take the initiative to have intestinal health checkups. Due to the effectiveness of preventive measures and health education, the incidence and mortality rate of colorectal cancer in the United States are now in a declining stage, while the incidence and mortality rate of colorectal cancer in China are in a rapidly increasing stage. The symptoms of colorectal cancer are relatively insidious, and patients may not have obvious local symptoms in the early stage of the disease or even in the late stage of the disease, so that many patients are already in the middle or late stage when they are diagnosed, and the treatment effect is greatly reduced. Therefore, health check of the intestinal tract is especially important. And early colorectal cancer has no specific symptoms. How to detect colorectal cancer in early stage through physical examination? More than half of colorectal cancers occur in the rectum, and 80% of rectal cancers belong to the middle and low level, which can be detected by rectal anal finger examination and make preliminary judgment on perianal diseases and colorectal cancer. The rectum of adults is generally 15 cm long, and the rectal intestinal wall below 7-8 cm from the anal opening can be directly palpated by hand, and nodules on the rectal mucosa can be found by slight elevation. More than half of the colorectal cancer patients in China are rectal cancer, and among the rectal cancer patients, about 60-70% are middle and low rectal cancer. In other words, 70% of rectal cancers (about one-third of colorectal cancers) can be detected by anal finger examination. If the doctor finds mucus on the finger sleeve during this examination, it means that there is purulent blood discharge in the patient’s rectum, and if there is dark red blood, it may indicate intestinal bleeding, and if it is bright red, it may be bleeding hemorrhoids. Most rectal cancers, especially low-grade rectal cancers, can be detected by rectal finger examination. In addition, the shape, texture and mobility of the cancer can also be clarified through rectal examination. 2.Fecal occult blood test The fecal occult blood test has important value for the diagnosis of gastrointestinal bleeding and is often used as a screening indicator for the early diagnosis of gastrointestinal malignancies. Why do occult blood test to screen colorectal cancer: when there is a small amount of bleeding in the digestive tract, there is usually no blood in stool, black stool and other manifestations, and there is no abnormality in the appearance of stool to the naked eye, but the stool occult blood test can make a judgment on a very small amount of bleeding in the digestive tract. In fact, not only colorectal cancer, but also gastrointestinal tumors such as gastric cancer, in the early stage of tumor development, the tumor will erode the mucosa and submucosa blood vessels, resulting in very small amount of gastrointestinal bleeding, which is difficult to judge with the naked eye. For people without a history of gastric disease, if a positive fecal occult blood test is found during physical examination, it is recommended to do it again at a later time. If it is still or continues to be positive, then it is necessary to be alert, first of all, to exclude gastrointestinal tumors, the most common sites of gastrointestinal tumors are stomach, colon and duodenum, and to do further colonoscopy or gastroscopy under the advice of a specialist. The chance of people developing colorectal cancer increases significantly after the age of 40. According to statistics, about 75% of colorectal cancer patients are in this age group. Therefore, people should do fecal occult blood test once a year from the age of 40 to be alert to the bleeding caused by polyps or tumors. 3.Colonoscopy Colonoscopy is the most effective means to detect early colorectal cancer. Colonoscopy not only can clearly observe the intestinal tract, but also can take suspicious lesions for pathological examination under direct vision, which is conducive to the detection and confirmation of early and micro colorectal cancer. At present, few people take the initiative to do colonoscopy for two main reasons: firstly, people lack knowledge about colorectal cancer, and secondly, people are difficult to accept or even afraid of such invasive examination method as colonoscopy. This kind of fear makes many patients delay their conditions, resulting in many clinical cases of colorectal cancer not being diagnosed and treated at an early stage and missing the opportunity for treatment. Another major significance of colonoscopy is that it can detect and deal with colon polyps, especially adenomatous polyps and other precancerous lesions through minimally invasive endoscopy. We know that most colorectal cancers originate from adenomatous carcinoma. It may take several years or even longer from the occurrence of adenoma to the onset of cancer. If adenoma can be detected through colonoscopy and minimally invasive treatment through endoscopy at the asymptomatic stage when adenoma is not cancerous or early cancerous, the chance of its transformation to cancer can be blocked. Screening of high-risk groups should be enhanced. Theoretically, half of the children of patients with familial polyposis will develop colon polyposis, and they will pass the disease on to their offspring. Therefore, screening for high-risk groups who are prone to colorectal cancer should be enhanced, mainly for the following categories of people: 1. Parents, siblings and children who have one of them with colorectal cancer should have fecal occult blood test and colonoscopy from the age of 40. 2. People with familial adenomatous polyps are affected because of defects in their associated genes. Patients with this disease almost always develop colon cancer after the age of 40. Therefore, all members of such families should have regular colonoscopies starting from adolescence. 3. Patients with ulcerative colitis are at greater risk of developing colorectal cancer, and this risk usually begins eight years after the patient’s onset. Therefore, patients with total colitis should have a colonoscopy every 1-2 years after 8 years of illness. Patients with left hemicolectasis should have a colonoscopy every 1-2 years after 15 years of disease. 4.In the past, it has been believed that the polyps of patients with nigrostriatal polyposis will not become cancerous. However, recent clinical data show that the chance of malignant transformation of melanotic polyposis is 20%-23%. Therefore, patients with melanotic polyposis should also undergo regular checkups. Colorectal cancer mainly includes colon cancer and rectal cancer. In recent years, the incidence rate of colorectal cancer in China has been increasing year by year, and only 5% of all patients with colorectal cancer can be diagnosed at an early stage. Clinically, the early diagnosis rate of colorectal cancer is low, which is mainly because people do not pay enough attention to the early signs of the disease. Colorectal cancer is a curable disease In the past decade, with the continuous development of science, significant progress has been made in the diagnosis and treatment of colorectal cancer. The biology of colorectal cancer, as well as the genetic mechanisms involved in tumorigenesis, are better understood. As a result, lesions can be detected at an earlier stage and a better staging system can be established using molecular genetic monitoring; surgical techniques can be improved to reduce postoperative mortality and recurrence rates; and the emergence of highly effective therapeutic drugs has led to the continuous updating of colorectal cancer treatment protocols, resulting in longer survival and better quality of life, and even early stage patients can be cured. Therefore, cancer treatment emphasizes the word “early”, early detection, early diagnosis and early treatment. General population: It refers to those who are not at high risk of colorectal cancer, and we recommend that these people can start to receive colorectal cancer screening after the age of 45, and the examination should be conducted once every 5-10 years on average. For high-risk groups, excluding those with family history, we recommend to start screening for colorectal cancer around the age of 40, with an average of once every 3-5 years. People with family history: For people with family history, we recommend early consultation at a large oncology center to determine whether the group has a genetic predisposition through careful collection of family history and some necessary tests, including genetic testing, by experienced clinicians. If there is a genetic predisposition, the patient will be followed closely by the clinician according to a specific follow-up protocol for hereditary tumors. If there is no apparent genetic predisposition, the population is followed up according to the screening protocol for high-risk groups. Fecal occult blood test and anal examination finger examination can be used as screening tools for colorectal cancer, which can provide clues for early diagnosis and are recommended once a year. Before colonoscopy becomes universally available, fecal occult blood test and anal examination finger examination are good supplements.