Introduction to the site of colorectal cancer

The incidence and mortality of colorectal cancer are also getting worse year by year. Colorectal cancer is a malignant tumor originating from the colon mucosal epithelium. So, where are the common sites of colorectal cancer? What are the symptoms?

Since benign tumors such as intestinal polyps are precancerous lesions, the most common sites for colorectal polyps are also the most common sites for colorectal cancer. A large number of clinical observations have found that 150% of cancers occur in the rectum, and 125% occur in the sigmoid colon (mainly at the rectosigmoid junction), which means that 75% of colorectal cancers occur on the left side, followed by the ileocecal region on the right side.

The main function of the large intestine is to absorb water from food residues, gradually forming them into feces and excreting them out of the body.

As food residues move through the large intestine, water is gradually absorbed and by the time they reach the sigmoid colon, they have formed feces. At this time, the harmful substances and carcinogens in the feces are also highly concentrated and will become difficult to excrete from the body if they are not discharged in time.

Under the action of some bacteria in the intestine, it will produce adverse stimulation to the intestinal mucosa over time, causing the intestinal mucosa to be damaged by inflammatory reactions such as congestion, exudation, and edema. In the process of repairing the damage, some genes of intestinal epithelial cells may mutate, become defective, and lose their normal functions, causing atypical hyperplasia and tumor-like hyperplasia of the intestinal epithelium, and eventually malignant transformation and becoming colorectal cancer.