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There's no sure way to prevent colorectal cancer. But there are things you can do that might help lower your risk, such as changing the risk factors that you can control.
Screening is the process of looking for cancer or pre-cancer in people who have no symptoms of the disease. Regular colorectal cancer screening is one of the most powerful tools for preventing colorectal cancer.
From the time the first abnormal cells start to grow into polyps, it usually takes about 10 to 15 years for them to develop into colorectal cancer. With regular screening, most polyps can be found and removed before they have the chance to turn into cancer. Screening can also find colorectal cancer early, when it's small and easier to treat.
If you’re age 45 or older, you should start getting screened for colorectal cancer. Several types of tests can be used. Talk to your health care provider about which ones might be good options for you. No matter which test you choose, the most important thing is to get tested.
If you have a strong family history of colorectal polyps or cancer, talk with your doctor about your risk. You might benefit from genetic counseling to review your family medical tree to see how likely it is that you have a family cancer syndrome.
You might be able to lower your risk of colorectal cancer by managing your diet and physical activity.
Weight: Being overweight or obese increases the risk of colorectal cancer in both men and women, but the link seems to be stronger in men. Staying at a healthy weight may help lower your risk.
Physical activity: Being more active lowers your risk of colorectal cancer and polyps. Regular moderate to vigorous activity can lower the risk. Limiting your sitting and lying down time may also lower your risk. Increasing the amount and intensity of your physical activity may help reduce your risk.
Diet: Overall, diets that are high in vegetables, fruits, and whole grains, and low in red and processed meats, probably lower colorectal cancer risk, although it’s not exactly clear which factors are important. Many studies have found a link between red meats (beef, pork, and lamb) or processed meats (such as hot dogs, sausage, and lunch meats) and increased colorectal cancer risk.
In recent years, some large studies have shown conflicting evidence that fiber in the diet probably lowers colorectal cancer risk. Research in this area is still under way. Recent studies looking specifically at whole grain intake, however, show that colorectal cancer risk appears to go down as you add more whole grains to your diet.
Limiting red and processed meats and eating more vegetables, fruits, and whole grains may help lower your risk.
Alcohol: Several studies have found a higher risk of colorectal cancer with increased alcohol intake, especially among men. It is best not to drink alcohol. For people who do drink, they should have no more than 1 drink per day for women or two drinks per day for men. Not drinking alcohol may help reduce your risk.
For more about diet and physical activity, see the American Cancer Society Guidelines for Diet and Physical Activity for Cancer Prevention.
Long-term smoking is linked to an increased risk of colorectal cancer, as well as many other cancers and health problems. Quitting smoking may help lower you risk of colorectal cancer and many other types of cancer, too. If you smoke and would like help quitting, call the American Cancer Society at 1-800-227-2345.
Some studies suggest that taking a daily multi-vitamin containing folic acid, or folate, may lower colorectal cancer risk, but not all studies have found this. In fact, some studies have hinted that folic acid might help existing tumors grow. More research is needed in this area.
Some studies have suggested that vitamin D, which you can get from sun exposure, in certain foods, or in a vitamin pill, might lower colorectal cancer risk. Studies have shown that low vitamin D levels are associated with an increased risk of colorectal cancer as well as other cancers. Because of concerns that excess sun exposure can cause skin cancer, most experts do not recommend this as a way to lower colorectal cancer risk at this time. More studies are needed to determine if increasing vitamin D intake from a supplement can help prevent colorectal cancer. Avoiding a low vitamin D level may be helpful; it is best to talk with your doctor about whether your vitamin D level should be tested.
Low levels of dietary calcium have been linked with an increased risk of colorectal cancer in some studies. Other studies suggest that increasing calcium intake may lower colorectal cancer risk. Calcium is important for a number of health reasons aside from possible effects on cancer risk. But because of the possible increased risk of prostate cancer in men with high calcium/dairy product intake, and the possible lower risk of other cancers like colorectal cancer and breast cancer, the American Cancer Society does not have any specific recommendations regarding dairy food consumption for cancer prevention.
Calcium and vitamin D might work together to reduce colorectal cancer risk, as vitamin D aids in the body’s absorption of calcium. Still, not all studies have found that supplements of these nutrients reduce risk.
A few studies have found a possible link between a diet that's high in magnesium and reduced colorectal cancer risk, especially among women. More research is needed to determine if this link exists.
Many studies have found that people who regularly take aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen (Motrin, Advil) and naproxen (Aleve), have a lower risk of colorectal cancer and polyps.
But aspirin and other NSAIDs can cause serious or even life-threatening side effects, such as bleeding from stomach irritation or stomach ulcers, which may outweigh the benefits of these medicines for the general public. For this reason, the American Cancer Society does not recommend taking NSAIDs just to lower colorectal cancer risk if you are someone at average risk.
Still, for some people in their 50s who have a high risk of heart disease, where low-dose aspirin is found to be beneficial, the aspirin may also have the added benefit of reducing the risk of colorectal cancer.
Because aspirin or other NSAIDs can have serious side effects, check with your doctor before starting any of them on a regular basis.
Some studies have shown that taking estrogen and progesterone after menopause (sometimes called menopausal hormone therapy or combined hormone replacement therapy) may reduce a woman’s risk of developing colorectal cancer, but other studies have not.
Because taking estrogen and progesterone after menopause can also increase a woman’s risk of heart disease, blood clots, and cancers of the breast and lung, it's not commonly recommended just to lower colorectal cancer risk.
If you're considering using menopausal hormone therapy, be sure to discuss the risks and benefits with your doctor.
The American Cancer Society medical and editorial content team
Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.
American Cancer Society. Colorectal Cancer Facts & Figures 2020-2022. Atlanta, Ga: American Cancer Society; 2020.
Chlebowski RT, Wactawski-Wende J, Ritenbaugh C, Hubbell FA, Ascensao J, Rodabough RJ, et al. Estrogen plus progestin and colorectal cancer in postmenopausal women. N Engl J Med. 2004 Mar 4;350(10):991-1004.
Kelly SR and Nelson H. Chapter 75 – Cancer of the Rectum. In: Niederhuber JE, Armitage JO, Dorshow JH, Kastan MB, Tepper JE, eds. Abeloff’s Clinical Oncology. 6th ed. Philadelphia, Pa. Elsevier: 2020.
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National Cancer Institute. Physician Data Query (PDQ). Colorectal Cancer Prevention. 2019. Accessed at https://www.cancer.gov/types/colorectal/patient/colorectal-prevention-pdq on February 23, 2020.
Rock CL, Thomson C, Gansler T, et al. American Cancer Society guideline for diet and physical activity for cancer prevention. CA: A Cancer Journal for Clinicians. 2020;70(4). doi:10.3322/caac.21591. Accessed at https://onlinelibrary.wiley.com/doi/full/10.3322/caac.21591 on June 9, 2020.
Last Revised: June 9, 2020
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