You will find known risk factors of colorectal cancer below. Not all of these risk factors will cause this cancer, but they may be contributing factors. It’s important to remember that risk factors are never a definitive cause of disease, as some people with many risk factors will never develop cancer, and others with no risk factors will develop it.
- Risk increases with age, with the average age at diagnosis being above 50 years old.
- Diets low in fruit & vegetables and fibre, and high in meats and fats seem to increase risk of colorectal cancer. This risk decreases with high fibre, low-fat diets, and less consumption of red or processed meat.
- Polyps or adenomas
- When found in the colon, polyps should always be removed and tested for cancer. Most do not contain cancer, but if left in place, they may develop into cancer – which is why they are referred to as precancerous.
- Family history of colorectal cancer
- The number of affected relatives, as well as their ages at time of diagnosis, is important information to estimate risk.
- Inflammatory bowel disease
- Ulcerative colitis and Crohn’s disease are known to increase risk of colon cancer, and this risk increases more for patients who develop colitis at an early age.
- Use of alcohol
- Having two or more drinks per day is an important risk factor, especially in men.
- Body fat
- Low physical activity levels
- Previous rectal cancer
- Rectal cancer has a higher recurrence rate than colon cancer, and close follow-up is necessary for these patients.
Information taken from BC Cancer.