Prevention

Exercise

Studies indicate that daily exercise is one of the best ways to reduce the risk of colorectal cancer. The more vigorous the activity, the greater the benefit, but even moderate exercise (walking, stair-climbing) can help reduce colorectal cancer risk. The American Cancer Society (ACS) recommends that people engage in at least moderate exercise for 30 minutes or more at least 5 days a week. The ACS also notes that 45 minutes or more of moderate to vigorous activity at least 5 days a week may help further reduce cancer risk.

Some studies also suggest that regular exercise may be beneficial for patients who have been diagnosed with colorectal cancer. Two 2006 studies indicated that exercise may reduce the risk of colorectal cancer recurrence and death for patients with stage I - III cancer.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

NSAIDs are very common pain relievers that are available over-the-counter and by prescription. They include aspirin, acetaminophen (Tylenol), naproxen (Aleve), and the COX-2 inhibitor celecoxib (Celebrex). Several studies have reported that NSAIDs can help reduce the risk of colorectal cancer. However, regular use of NSAIDs, even in low doses, can increase the risk of gastrointestinal bleeding and stomach ulcers. Several 2006 studies in the New England Journal of Medicine reported that celecoxib prevented precancerous polyps, but the drug more than doubled patients’ risk for heart attack and other cardiovascular events.

A 2005 Nurse’s Health Study found that aspirin, but not other NSAIDs, does provide protection against colorectal cancer. However, the risk was only reduced for women who took 2 aspirin a day for more than 10 years. In addition, this dose level greatly increases the risk for gastrointestinal bleeding. At this time, the American Cancer Society does not recommend that people take NSAIDs, or other types of medication, for colorectal cancer prevention.

5-ASAs

Medications containing 5-aminosalicylate (5-ASA) are sometimes given to patients with ulcerative colitis to help control inflammation. These drugs, which include sulfasalazine and mesalamine, are chemically related to aspirin. A 2005 review of clinical trials found that patients with ulcerative colitis who used 5-ASA were 49% less likely to develop colorectal cancer than patients who did not use these drugs

Statins

Some studies have suggested that cholesterol-lowering statin drugs may help reduce colorectal cancer risk. A 2006 study in the Journal of the National Cancer Institute did not find any protective benefit for statins.

Estrogen in Women

Estrogen has been associated with a lower risk for colon cancer, perhaps because of specific enzymes that prevent cell proliferation. Drugs containing estrogen, then, may help high-risk women:

  • There is some evidence that hormone replacement therapy (HRT) reduces the risk of colon cancer in postmenopausal women. It carries other risks, however, including a higher risk for breast and uterine cancer and blood clots. A 2004 New England Journal of Medicine study found that while short-term use of estrogen plus progestin reduced the risk of developing colon cancer, combination HRT users who were diagnosed with the disease had more advanced forms of the cancer. Older women who are at higher risk for colon cancer might discuss risks and benefits of HRT with their doctor.
  • Oral contraceptives may reduce younger women's risk of colon cancer. Duration of use does not seem to be associated with decreased risk, but protection appears stronger for women who have more recently used oral contraceptives.
Review Date: 9/1/2006
Reviewed By: Harvey Simon, M.D., Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital