Colon cancer is a common malignant tumor of the gastrointestinal tract occurring in the colon area, with the highest incidence rate in the age group of 40-50 years old, and the ratio of men to women is 2-3:1. It is one of the fastest rising tumors in most countries and regions in the world in recent decades in terms of incidence and death. In Europe and the United States, its incidence rate ranks second among malignant tumors. In China, its incidence rate is generally around the fifth or sixth place in the past. From the epidemic trend in recent years, with the change of people’s lifestyle and diet, the number of patients with the disease is also increasing, especially in developed cities or regions such as Beijing and Shanghai. According to the information of Beijing Institute of Cancer Control, there are about 20,000 new cancer patients in Beijing every year, among which colon cancer ranks the second. Colon cancer is a preventable cancer, and those with early cases without lymph node metastasis have the greatest hope of cure, and the 5-year survival rate after surgical resection can reach over 90%. However, it is very unfortunate that most of the patients who die of colon cancer die not from the disease itself but from the ignorance of colon cancer. Therefore, it is very necessary to understand the knowledge about colorectal cancer. People who are prone to colon cancer include people with obesity, high-protein, high-calorie, low-fiber diet, people with family history of colon cancer, people with history of colon polyps and family history, whose main reasons are high-fat recipes and insufficient fiber intake. The key to improve the cure rate of early colon cancer is early detection, timely diagnosis and proper treatment. Colon cancer grows slowly, so early detection of cancer, strangling it in the breeding stage, controlling the disease and combining with effective treatment can completely achieve the purpose of eradication, that is, maximizing the cure rate of early colon cancer. The early symptoms of colon cancer are mostly atypical, and usually there will be symptoms only when it has developed to a certain degree, so it is easy to be misdiagnosed clinically. If necessary examinations can be conducted timely for suspicious symptoms and highly alert to the danger signals of colon cancer, the early diagnosis rate can be improved and a good foundation can be laid. Important early signs of colon cancer: 1. blood in stool; 2. change in stool habit; 3. change in stool trait; 4. unexplained anemia. In addition, depending on the location of colon cancer, there are different manifestations: the right hemicolectomy is mainly characterized by systemic symptoms, including emaciation, anemia, right abdominal discomfort, etc. The left hemicolectomy is mainly characterized by infarction. The left hemicolectomy is mainly characterized by obstructive symptoms, including abdominal pain, abdominal distension, and occasional palpable masses. It is clinically found that many colorectal cancer patients, especially colon cancer patients, are concomitant with some degree of anemia when their tumors are detected. Anemia can be manifested as dizziness, weakness, fear of cold, dry skin, as well as headache, insomnia, memory loss, panic, shortness of breath, loss of appetite, gastrointestinal disorders, etc., which cause great harm to the body. The cold weather in winter is more likely to lead to poor blood circulation, making these symptoms more obvious. However, many patients mistake anemia as “fear of cold” or simply think it is blood deficiency and take tonic drugs indiscriminately to delay treatment. Therefore, the best way to determine whether you are anemic or not is not based on subjective feelings alone, but to go to the hospital for routine blood tests. In medical science, if the red blood cell count, hemoglobin amount and red blood cell pressure volume in a certain volume of circulating blood are lower than the normal standard, the most important one is hemoglobin, which is below 120g/L (12.0g/dl) for adult male and 110g/L (11.0/dl) for adult female, it is generally considered as anemia. Iron deficiency anemia caused by intestinal cancer is characterized by high and sometimes low hemoglobin or always difficult to correct after iron supplementation treatment. It is not uncommon for colon cancer to have iron deficiency anemia as its first manifestation, but in its early stage, patients do not have abdominal pain, bloating, constipation and diarrhea alternately, and there is no abdominal mass to be found, and there are no symptoms of colon cancer such as solving thick blood stool, so it is very easy to be missed. Therefore, if the above-mentioned discomfort symptoms occur, you should go to hospital for routine blood tests to confirm. The presence of colon cancer leads to chronic and long-term bleeding in the digestive tract, and the presence of tumors in the colon, which is the main part of nutrient absorption, also affects the absorption of nutrients into the body. Anemia caused by colon cancer is different from anemia caused by malnutrition, and nutritional anemia can be treated by supplementing nutrients or medication. However, if the anemia is caused by colorectal cancer, because the cancer cells infiltrate and destroy the mucous membrane and submucous blood vessels in the inner wall of colon, it will cause the patient to lose blood slowly, which is like a bottomless hole, the top is filled in and the bottom is leaked out, so the patient’s iron deficiency anemia is always difficult to be corrected, and the conventional blood supplementation methods cannot achieve the effect of blood replenishment. Many patients have unexplained anemia, but they cannot find out any cause when they go to hematology department, so they have been treated as iron deficiency anemia, and after treatment, they find that the anemia has worsened, and when they look deeper into the cause of anemia, they actually have colon cancer. A new study published in the latest British Journal of Colorectal Diseases found that such unexplained iron deficiency anemia is likely to be an early symptom of colorectal cancer. Dr. Damery, a professor at Durham University in the United Kingdom, and colleagues studied at least 628,000 patients over the age of 40. Participants were screened for iron deficiency anemia and it was found that 1/3 of the patients with iron deficiency anemia went on to develop colon cancer. According to foreign data, the 5-year survival rates of patients with stage I, II, III and IV colorectal cancer were 93%, 84%, 44% and 8%, respectively. It can be seen that early detection, early diagnosis and early treatment are the keys to improve the efficacy of intestinal malignant tumors. Therefore, when middle-aged and elderly people have abdominal pain, diarrhea and blood in stool, or people with family history of colorectal cancer, especially those who prefer to eat high protein, high fat and less exercise, if they cannot relieve anemia through dietary therapy or medication, they must seek medical consultation and clear diagnosis in time.