Colorectal Cancer: Risk, Screening & Prevention

Pictured: Josephine Abat & Moshe Shike Gastroenterologist and nutritionist Moshe Shike, in clinic here with nurse Josephine Abat, recommends screening based on each individual’s risk for developing colorectal cancer.

A number of factors can increase a person’s risk of developing colorectal cancer. The good news, though, is that there are steps you can take to protect yourself.

In most cases, you can prevent colorectal cancer by undergoing screening to detect and remove polyps from the colon before they become cancerous. This examination is called a colonoscopy.

Colonoscopies have been shown to significantly reduce the chance of developing colorectal cancer.(1) Even in people who develop colorectal cancer, the disease can usually be cured if caught early enough — the five-year survival rate for colorectal cancer detected at an early stage is about 90 percent.(2)

This does not mean that screening is for everyone, though. At Memorial Sloan Kettering, we recommend cancer screening based on your individual risk for developing the disease. Factors such as your age, family medical history, and genetics can affect your level of risk.

Learn more about our screening guidelines for colorectal cancer.

Factors That Increase Risk of Colorectal Cancer

Many factors can increase your risk of developing colorectal cancer. Some are beyond your control, but others can be affected by your lifestyle.


Our colorectal cancer experts emphasize the benefits of colonoscopy, a screening and cancer prevention tool that is used to remove precancerous polyps.


Some of the main factors that cannot be changed include:

  • Age: Most cases occur in people in their 60s and 70s. Cases before age 50 are relatively uncommon unless there is a family history of early colorectal cancer.
  • Polyps: The presence of polyps in the colon increases risk, especially if they are large or if there are many of them.
  • Personal history of colorectal cancer: Someone previously diagnosed and treated for colorectal cancer is at higher risk for developing it again.
  • Personal history of bowel disease: Inflammatory bowel diseases (including ulcerative colitis or Crohn's colitis) increase your risk of colorectal cancer because they inflame the colon over extended periods of time.
  • History of ovarian, uterine, or breast cancer: Women who have had any of these cancers are at higher risk.
  • Family history of colorectal cancer: Someone with a family history of the disease, especially in a parent or sibling before the age of 55 or multiple relatives at any age, is at a higher risk.
  • Genetics: About 20 percent of colon cancer cases arise because of specific genetic mutations.

Studies indicate that certain lifestyle factors increase your risk for colorectal cancer. These include:

  • A diet that is high in red, processed, or heavily cooked meats
  • Lack of exercise
  • Obesity, particularly having excess fat in the waist area, rather than the hips or thighs
  • Cigarette smoking: Studies indicate that smokers are 30 to 40 percent more likely than nonsmokers to die of colorectal cancer because they are more likely to develop polyps.
  • Heavy alcohol consumption

Lifestyle Habits That Reduce Risk of Colorectal Cancer

There are many healthful lifestyle habits you can follow to reduce your risk:

Eat less animal and dairy fat and more fruits, vegetables, and fiber. The American Cancer Society recommends eating at least five servings of fruits and vegetables each day and several servings of other foods from plant sources, such as whole grain breads, cereals, grains, rice, pasta, or beans.

Get more exercise. Even regular, moderate physical activity such as taking the stairs instead of an elevator, raking leaves, or walking can help reduce your risk.

Maintain a healthy weight. Obesity has been identified as a risk factor for colorectal cancer, so maintaining a healthy weight can reduce your risk.

Other Dietary Factors

Some studies have suggested that the following vitamins and minerals may reduce your risk of colorectal cancer:

  • vitamin D
  • calcium
  • magnesium
  • folic acid

However, more research is needed before doctors can recommend that you take these nutrients in supplement form to reduce the risk of colorectal cancer.

Aspirin and Other NSAIDs

Many studies have found that people who regularly use aspirin or other nonsteroidal antiinflammatory drugs (NSAIDS) such as ibuprofen, naproxen, or celecoxib for arthritis, have a lower risk of colorectal cancer and polyps. Other studies have demonstrated that aspirin can prevent the growth of polyps in people who were previously treated for early stages of colorectal cancer or who had previously had polyps removed from the colon.

However, aspirin and other NSAIDs can have serious side effects. Aspirin can cause stomach bleeding in some people, and drugs such as celecoxib (Celebrex®) may increase the risk of heart attack and stroke. For these reasons, doctors are not yet ready to recommend that people take aspirin or other NSAIDs specifically to reduce colorectal cancer risk.

Hormone-Replacement Therapy

Some studies have shown that women who use hormone-replacement therapy (HRT) consisting of estrogen and progesterone after menopause have a reduced risk of colon cancer. However, large studies have also shown that postmenopausal HRT can pose health risks not related to colorectal cancer. The decision to use HRT is one that should be made between you and your healthcare provider after discussing the potential benefits and risks.

The National Cancer Institute provides current information about risks and benefits of postmenopausal hormone use on their website.

  1. Sidney J. Winawer, Ann G. Zauber, May Nah Ho, Michael J. O'Brien, Leonard S. Gottlieb, Stephen S. Sternberg, Jerome D. Waye, Melvin Schapiro, John H. Bond, Joel F. Panish, Frederick Ackroyd, Moshe Shike, Robert C. Kurtz, Lynn Hornsby-Lewis, Hans Gerdes, Edward T. Stewart, and the National Polyp Study Workgroup. Prevention of Colorectal Cancer by Colonoscopic Polypectomy. N Engl J Med. 1993 Dec 30;329(27):1977-1981.
  2. Altekruse SF, Kosary CL, Krapcho M, Neyman N, Aminou R, Waldron W, Ruhl J, Howlader N, Tatalovich Z, Cho H, Mariotto A, Eisner MP, Lewis DR, Cronin K, Chen HS, Feuer EJ, Stinchcomb DG, Edwards BK (eds). SEER Cancer Statistics Review, 1975-2007, National Cancer Institute. Bethesda, MD,, based on November 2009 SEER data submission, posted to the SEER website, 2010.