Introduction

According to the World Health Organisation and the International Agency for Research on cancer, colorectal cancer is a major cause of morbidity and mortality throughout the world and accounts for over 9% of all cancer incidences is the third most common cancer worldwide and the fourth most common cause of death. It affects men and women almost equally.

In this blog, the focus is mostly on the known risk factors associated with colorectal cancer, since it is mostly lifestyle-related which implies that it is reversible, except the familial and hereditary factors. However, when a family is aware that a certain condition might occur, the family members should be informed to consult with their doctor about screening in order to prevent or identify the condition.

The development of colon cancer and the associated risk factors

A concise overview of known risk factors is provided, including familial and hereditary factors, as well as environmental lifestyle-related risk factors such as physical inactivity, obesity, smoking and alcohol consumption. The colon and the rectum are the final portions of the tube that extends from the mouth to the anus. Although the large intestine is a tube, it is structurally a complicated tube, more like a garden hose. The tube is comprised of four layers.

The first layer (the inner) of cells that line the cavity through which the undigested and digested food travels, called the mucosa, which is attached to a thin second layer, the submucosa, that is attached to a layer of muscle, the muscularis is. The entire tube is surrounded by fibrous (scar-like) tissue called the serosa.

The most common cancers of the large intestine (the type called adenocarcinoma) arise from the mucosa, the inner layer of cells. These cells are exposed to toxins from food and bacteria as well as mechanical wear and tear, and they are relatively turning over rapidly (dying off and being replaced). Mistakes (usually a series of mistakes involving genes within the replacement cells) lead to abnormal cells and uncontrolled proliferation of the abnormal cells that give rise to cancer. The rapid turnover allows for more mistakes to occur as compared with tissues that do not turn over so rapidly (for example, liver tissue).

Risk factors

• Increasing age is the main risk factor for colorectal cancer. Around 90% of colorectal cancers are diagnosed after age 50.
• Common risk factors for colorectal cancer include increasing age, African-American race, a family history of colorectal cancer, colon polyps, and long-standing ulcerative colitis.
• Most colorectal cancers develop from polyps. Removal of colon polyps can aid in the biopsy confirmation of cancerous tissue.
• African Americans have a higher incidence of colorectal cancer than people of other races.
• Diets high in fat have been shown in numerous research studies to predispose people to colorectal cancer.
• Colorectal cancer is a malignant tumor arising from the inner wall of the large intestine (colon) or rectum.
• Colorectal cancer is the third leading cause of cancer in both men and women in the U.S.
• Treatment of colorectal cancer depends on the location, size, and extent of cancer spread, as well as the health of the patient.
• Surgery is the most common medical treatment for colorectal cancer.