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Understanding your colorectal cancer risk

Colorectal cancer risk factors are things that increase the chance that you could get colorectal cancer. Some risk factors you can control, such as drinking alcohol, diet, and being overweight. Others, such as family history, you cannot control.

The more risk factors you have, the more your risk increases. But it does not mean you will get cancer. Many people with risk factors never get cancer. Other people get colorectal cancer but do not have any known risk factors.

Learn about your risk and what steps you can take to prevent colorectal cancer.

Risk Factors

We do not know what causes colorectal cancer, but we do know some of the things that may increase the risk of getting it, such as:

  • Age. Your risk increases after age 50
  • You have had colon polyps or colorectal cancer
  • You have inflammatory bowel disease (IBD), such as ulcerative colitis or Crohn disease
  • Family history of colorectal cancer or polyps in parents, grandparents, siblings, or children
  • Gene changes (mutations) in certain genes (rare)
  • African American or Ashkenazi Jews (people of Eastern European Jewish descent)
  • Type 2 diabetes
  • Diet high in red and processed meats
  • Physical inactivity
  • Obesity
  • Smoking
  • Heavy alcohol use

How to Reduce Your Risk

Some risk factors are in your control, and some are not. Many of the risk factors above, such as age and family history, can't be changed. But just because you have risk factors you can't control doesn't mean you can't take steps to lower your risk.

Start by getting colorectal cancer screenings (colonoscopy) at age 40 to 50 depending on risk factors. You may want to start screening earlier if you have a family history. Screening can help prevent colorectal cancer, and it is one of the best things you can do to lower your risk.

Certain lifestyle habits also may help lower your risk:

  • Maintain a healthy weight
  • Eat a low-fat foods with plenty of vegetables and fruits
  • Limit red meat and processed meat
  • Get regular exercise
  • Limit alcohol to no more than 1 drink per day for women and 2 drinks per day for men
  • Do not smoke
  • Supplement with vitamin D (talk to your health care provider first)

You can also have genetic testing done to assess your risk for colorectal cancer. If you have a strong family history of the disease, talk with your provider about testing.

Low-dose aspirin may be recommended for some people who are at very high risk for colorectal cancer found with genetic testing. It is not recommended for most people because of side effects.

When to Call the Doctor

Call your provider if you:

  • Have questions or concerns about your colorectal cancer risk
  • Are interested in genetic testing for colorectal cancer risk
  • Are due for a screening test

Alternative Names

Colon cancer - prevention; Colon cancer - screening


Itzkowitz SH, Potack J. Colonic polyps and polyposis syndromes. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 126.

Lawler M, Johnston B, Van Schaeybroeck S, et al. Colorectal cancer. In: Niederhuber JE, Armitage JO, Kastan MB, Doroshow JH, Tepper JE, eds. Abeloff's Clinical Oncology. 6th ed. Philadelphia, PA: Elsevier; 2020:chap 74.

National Cancer Institute website. Colorectal cancer prevention (PDQ) - health professional version. www.cancer.gov/types/colorectal/hp/colorectal-prevention-pdq. Updated February 28, 2020. Accessed October 6, 2020.

US Preventive Services Task Force; Bibbins-Domingo K, Grossman DC, et al. Screening for colorectal cancer: US Preventive Services Task Force recommendation statement. JAMA. 2016;315(23):2564-2575. PMID: 27304597 pubmed.ncbi.nlm.nih.gov/27304597/.

Review Date 7/17/2020

Updated by: Michael M. Phillips, MD, Clinical Professor of Medicine, The George Washington University School of Medicine, Washington, DC. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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