Who is at risk for colorectal cancer?

Every one of us is at risk for colorectal cancer. Although the exact cause for the development of precancerous colon polyps that lead to colorectal cancer is not known, there are some factors that increase a person's risk of developing colorectal polyps and cancer. These risk factors include:

  • Age: The risk of developing colorectal polyps and cancer increases as we age. Colorectal cancer is more common in people over the age of 50, however, younger adults can also develop colorectal cancer.
  • Other medical conditions: Medical conditions (type 2 diabetes, previous history of cancer, history of inflammatory bowel disease) and inherited conditions (Lynch syndrome, familial adenomatous polyposis) can increase your chances of developing colorectal cancer.
  • Lifestyle factors: You may be at increased risk for developing colorectal cancer if you drink alcohol, use tobacco, don't get enough exercise, and/or if you are overweight. Smoking increases the risk of precancerous polyps and colorectal cancer. A diet high in fat and calories and low in fiber, fruits and vegetables has been linked to a greater risk of developing colorectal cancer. Many lifestyle factors that increase the risk of colorectal cancer can be modified to lessen that risk.

What conditions are associated with colorectal cancer?

  • Polyps: There are a variety of polyps that can form on the inner wall of the colon or rectum. Precancerous polyps can turn into colorectal cancer. People with numerous polyps—including adenomas, hyperplastic polyps or other types of polyps—often have a genetic predisposition to polyposis and colorectal cancer. These individuals should be managed differently than people with only one to two colorectal polyps.
  • Inflammatory bowel disease: Ulcerative colitis and Crohn's colitis are conditions in which the lining of the colon becomes inflamed. People with these conditions, when present for more than seven years and affecting a large portion of the colon, are at greater risk for developing colorectal cancer.
  • Personal history: A person who already has had colorectal adenomas or cancer may develop the disease a second time. Also, a history of inflammatory bowel disease can increase the risk of developing colorectal cancer.
  • Family history: Sometimes colon cancer “runs in” families. This type of moderately increased cancer risk can be called a "familial colon cancer." When a person has a hereditary cancer susceptibility, he or she has inherited a copy of a cancer susceptibility gene with a mutation. Individuals who inherit a mutation in a cancer susceptibility gene have a much greater chance for developing cancer. However, not everyone with a cancer susceptibility gene mutation will develop cancer. Genetic testing is available for all of these colorectal cancer syndromes.

Does having these risk factors mean that I will develop colorectal cancer?

Having one or more of these risk factors does not guarantee that you will develop colorectal cancer. However, you should talk about these risk factors with your doctor. He or she may be able to suggest ways to reduce your chances of developing colorectal cancer.

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