What are the specific causes of rectal cancer

Among the causes of rectal cancer, the clear cause is the direct connection with excessive intake of fat and protein, but other aspects have not been fully clarified. However, possible high-risk causes such as genetics and diet should be paid special attention to, as these aspects are summarized through clinical experience.

1. Genetic factors

Many families with colorectal cancer have a family history of cancer and many digestive tract tumors. Because the genes of normal cells change, cancer patients inherit a susceptibility, and with some stimulating factors, tissue cells grow rapidly and develop into cancer. Cell genetic genes mutate and become malignant cells with genetic characteristics, which manifests as a family history of cancer. This cause of colorectal cancer is relatively common.

2. Dietary factors

The so-called Western diet, which is high in fat, protein and low in fiber, is believed to be related to the occurrence of colorectal cancer. In areas with a high incidence of colorectal cancer in Western countries, the incidence of colorectal cancer is high. In contrast, the Banti tribe in South Africa consumes rough food that is low in fat and rich in fiber, and the incidence of colorectal cancer is low. If these residents immigrate to areas with a high incidence of colorectal cancer, the dietary structure will change, and the incidence will increase accordingly. This is because high-fat and high-protein foods can increase the amount of methylcholanthrene in feces, which can cause increased bile acid secretion and be decomposed into unsaturated polyunsaturated hydrocarbons by anaerobic bacteria in the intestines. Both of these substances are carcinogens. The reduction in fiber content slows down the speed of feces passing through the intestines, which increases the contact time between these carcinogens and the intestinal conjunctiva, leading to an increased chance of cancer.

3. Adenoma cancer

Tumor polyps can turn into cancer. Adenomas can be divided into three types: tubular adenomas, villous adenomas, and mixed adenomas. Tubular adenomas have a high incidence rate, and villous adenomas have a high rate of canceration. Among adenomas, there are hereditary familial adenomas, which are considered precancerous lesions. They usually occur after the age of 30, but some people may become cancerous before the age of 20.

4. Inflammatory bowel disease

Ulcerative colitis and Crohn's disease are caused by the destruction of intestinal mucosa, the proliferation of ulcer repair, and the formation of granulation tissue, which leads to cancer. Schistosoma japonicum eggs are deposited in the rectal mucosa, and chronic inflammation stimulates cancer.