Colon and rectal cancer, collectively known as colorectal cancer, is a high-risk gastrointestinal malignant tumor, second only to lung, stomach and liver cancer, and the incidence rate has taken the fourth place among common tumors. According to statistics, the rate of incidence in China is rising far beyond the international level of 2%, and is approaching 5%, with up to 400,000 new cases each year. What is more noteworthy is that this disease, which used to belong exclusively to the middle-aged and elderly, is gradually becoming younger and cases in their 20s are not rare. Worldwide, colorectal cancer accounts for 9.4% of all malignant tumor incidences in men and 10.1% in women. Globally, there are about 1.02 million new cases and 530,000 deaths per year, of which about 400,000 new cases and 7.35 deaths per 100,000 per year in China. Colorectal cancer is very common in economically developed regions and countries, and the high incidence of colorectal cancer in China is mainly concentrated in the Yangtze River Delta region and Pearl River Delta region, among which Suzhou, Zhejiang and Shanghai are the three most prevalent areas, and the incidence rate is close to that of developed countries in the West. As early symptoms of colorectal cancer are easily confused with other diseases, treatment is often delayed, and when it is found, it is already in advanced stage, and the prognosis is very poor. Early diagnosis and early treatment are the keys to improve the survival rate of colorectal cancer patients. Common symptoms of colorectal cancer include: 1. Blood in stool. This is one of the early symptoms of colorectal cancer, but the time and nature of colorectal cancer differs from one part to another. Patients with rectal cancer can have blood in stool in early stage, which can be fresh blood and often confused with hemorrhoids. Other parts of tumor bleeding sometimes cannot be detected by naked eyes due to the small amount of blood or long stay in the body, but the stool occult blood test is positive, and even serious anemia may appear in a long time. 2. Change of stool habit. It includes change of stool time and frequency, as well as constipation or unexplained diarrhea. Patients with rectal cancer may have more frequent stools, but not many stools each time, and may discharge some mucous jelly-like liquid and have the feeling of incomplete defecation. Some patients may have repeated alternating constipation and diarrhea. 3. Abnormal stool shape. The normal stool is cylindrical in shape, but if the cancer protrudes in the rectal cavity and presses the stool, the stool often becomes thinner when it is discharged, and it can also be flattened, and sometimes there are blood marks attached. 4.Recurrent untreated hemorrhoids, unexplained anemia and weight loss. The tumor growth is caused by constant bleeding and nutritional depletion. 5.Recurring unexplained stomach distension and pain. When tumor growth in the lumen of large intestine blocks the lumen, abdominal pain, bloating, nausea and vomiting can occur, and even intestinal obstruction such as stopping defecation and exhaustion when the lumen is completely blocked. Therefore, if the above-mentioned suspicious symptoms appear, you should seek medical consultation in time for early diagnosis and early treatment, so as not to miss the time of treatment.