What are the causes of colorectal cancer?

Causes of colorectal cancer include:

1. Dietary factors: A high-fat, high-meat, low-fiber diet is closely related to the occurrence of colorectal cancer. A high-fat diet can not only stimulate the increase in bile secretion, but also promote the growth of certain anaerobic bacteria in the intestine. Once cholesterol and bile salts are decomposed by anaerobic bacteria to form unsaturated cholesterol, such as deoxycholic acid and lithocholic acid, there are increases in the intestine. The latter two are carcinogens or cancer-promoting substances, and can therefore lead to the occurrence of colorectal cancer.

2. Genetic factors: About 1/4 of the families of patients with colorectal cancer have a family history of cancer, half of which are also digestive tract tumors. The risk of colorectal cancer in family members with a family history of colorectal cancer is 2-6 times higher than that of the general population. Several genes and genetic diseases cause great harm to colon cancer: familial polyposis, Turcot syndrome, Gardner syndrome, juvenile polyposis, Cowden's disease, neurofibromatosis.

3. Polyps According to statistics, the incidence of colorectal cancer in patients with colon polyps is about 5 times higher than that in patients without colon polyps. Familial multiple colon polyposis has a higher incidence of cancer. Most colorectal cancers occur on the basis of polyps. In the normal population, the incidence of polyps is 5% to 10%. In adults over 45 years old, the incidence of polyps is 10%. The incidence of rectal polyps increases with age.

4. Chronic inflammation stimulates the incidence of colorectal cancer in patients with ulcerative colitis, which is 5 to 10 times higher than that in the normal population. The incidence of colorectal cancer in patients with chronic bacterial dysentery, chronic amoebic enteropathy, and Crohn's disease is higher than that in the control population of the same age. Since chronic ulcerative colitis and other inflammations can cause intestinal mucosal exudation and edema, repeated destruction and repair processes can cause fibrous tissue hyperplasia, thickening of the intestinal wall, stenosis of the intestinal cavity, epithelial cell metaplasia, formation of multiple polyps and chronic granulomas, and then canceration.