Rectal cancer is a relatively common malignant tumor of the gastrointestinal tract, and it generally takes 5-8 years, or even longer, for rectal cancer to slowly form from nothing to something. It takes a process to form rectal cancer from nothing to something, from smooth intestinal wall to bulging benign polyps to adenomatous polyps and finally to precancerous disease, and then to develop into early in situ rectal cancer, each step takes 1-2 years or even longer, adding up to 5-8 years or even longer to form rectal cancer from nothing to something. Therefore, colonoscopy should be done in time, and even if there are no digestive symptoms, gastroscopy should be perfected at a certain age to detect various digestive tract tumors in time, so as to interrupt the process of rectal cancer formation and avoid its development into rectal cancer.