Colorectal cancer prevention and risk factors


The occurrence of colorectal cancer can be largely prevented by primary and secondary prevention. Read more in the article Cancer prevention.

Risk factors

The exact cause of colorectal cancer is unknown in most patients. However, there are some risk factors known to increase the risk of developing colorectal cancer.


Age is one risk factor for colorectal cancer. Colorectal cancer most typically occurs in people aged 75 and above, but can also affect younger people.

Colon polyps

Some types of polyps present another risk factors. Polyps are outgrowths from the intestinal wall. After a long time, some of these polyps give rise to carcinoma. It is therefore necessary to remove all polyps from the colon and rectum and to examine them carefully, just to make sure that they are really polyps and not carcinomas. Polyps can recur and therefore might need to be removed repeatedly.

Genetic predisposition

Genetic predisposition is also important for the development of colorectal cancer. The risk is higher if colorectal cancer occured in first-degree relatives, i.e. in parents, siblings or children. In some cases, the genetic disorder is so characteristic that colorectal cancer will almost certainly develop at some time in the future. These conditions involve, for example, the familial adenomatous polyposis (FAP).

Inflammatory bowel disease (IBD)

Some diseases, such as ulcerative colitis or Crohn’s disease, also increase the risk of developing colorectal cancer.

Dietary habits

Dietary habits play a significant role in health and mortality, and can be easily influenced, as opposed to many other risk factors. An excessive consumption of animal fats, red meat and processed meats has a definitely negative impact on our health, and significantly increases the risk of developing colorectal cancer. Energy-dense foods (foods high in fats and/or added sugars and/or low in fibre) are high in fats sugars and can be low in nutrients. These foods, especially when consumed frequently or in large portions, increase the risk of obesity, which in turn increases the risk of cancer. Furthermore, evidence shows that vegetables, fruits and other foods containing dietary fibre (such as wholegrains and pulses) may protect against a range of cancers including mouth, stomach and bowel cancer.

Excessive consumption of red meat and processed meat is one of the risk factors for colorectal cancer. Image credit: Alex Fox (

Figure 1: Excessive consumption of red meat and processed meat is one of the risk factors for colorectal cancer. (Image credit: Alex Fox /