Common questions and answers about colorectal cancer


What diet should I follow to prevent colorectal cancer from occurring? Are there any foods that actually cause colorectal cancer?

There are no foods that cause colorectal cancer. However, there appears to be a slightly increased risk of developing colorectal cancer in countries with higher red meat, processed meat, or non-dairy (meat-associated) fat intake. Similarly, decreased rates of colorectal cancer have been linked to increased fiber intake, though studies are not conclusive.  In general, experts recommend a diet high in vegetable fiber, low in fat, low in processed foods, and moderate to low amounts of red meat. There remain many unanswered questions in this area. No matter what your dietary intake is, remember to ask your doctor about the appropriate screening test to identify polyps and early cancers.

Can vitamins help prevent colon cancer?

Green vegetables, which are rich in the antioxidant vitamins C, E and beta-carotene and a good source of dietary fiber, seem to provide some protection against colorectal cancer. Tea catechins and related polyphenols may have a positive effect. Grape juice also may help inhibit development of colorectal cancer. Finally, calcium, vitamin D and, perhaps, folic acid appear to have protective effects in the colon. Clinical trials are needed to find out more. Be careful of over-the-counter dietary supplements touted to decrease the risk of colon (or any other) cancer. Let your doctor know if you are taking any over-the-counter medications to try to decrease your cancer risk, so he or she can make sure that they are right for you.

Does fiber play a protective role in colorectal cancer?

The question of whether fiber plays a protective role against colorectal cancer is controversial. Early studies suggested that fiber is indeed protective, whereas more recent and highly publicized studies find no protective effect. Pending additional studies that may resolve this controversy, a high-fiber diet is recommended because of its overall nutritional value, and because it promotes good bowel function. Furthermore, fiber is also beneficial for individuals with diabetes, heart disease, hypertension and a variety of other medical conditions.

Are there lifestyle changes that I can make to prevent colon cancer?

There are several lifestyle factors that seem to influence the risk of colon cancer. Smoking has been associated with an increased risk of multiple cancers including colon cancer. Additionally, being overweight or obese and leading a relatively inactive, sedentary lifestyle has been associated with an increased risk of colon cancer. In general we recommend leading a healthy lifestyle by incorporating routine exercise, maintaining a healthy weight, eating a nutritious diet, and abstaining from tobacco.  

Does an aspirin a day help?

There is evidence that suggests that people who are regularly taking aspirin or other non-steroidal anti-inflammatories such as ibuprofen and naproxen may have lower risks of colon cancer than others. However, these medications also may have unwanted side effects, such as stomach inflammation and ulcers. If your doctor has already prescribed aspirin to help protect your heart, you may also be lowering your risk of colon cancer. However, if you have not been put on an aspirin regimen by your doctor, do not start taking aspirin without consulting with your physician. It may not be right for you.

Six Questions That Could Save Your Life (or the Life of Someone You Love)

Test your knowledge about colorectal cancer (CRC) screening. If you think the answer is true or mostly true, answer true. If you think the answer is false or mostly false, answer false.

Six Questions That Could Save Your Life

  • 1. Colorectal cancer is predominantly a “man’s disease,” affecting many more men than women annually.

  • 2. Only people over the age of 50 who are currently experiencing some symptoms or problems should be screened for colorectal cancer or polyps.

  • 3. A colonoscopy screening exam typically requires an overnight stay in a hospital.

  • 4. Colorectal cancer is the second leading cause of cancer death among men and women combined in the United States.

  • 5. Tests used for screening for colon cancer include colonoscopy, fecal immunochemical (FIT) test, FIT-DNA or stool DNA test, FIT-fecal DNA, flexible sigmoidoscopy and CT colonography.

  • 6. Colorectal cancer is often preventable.


The American Society for Gastrointestinal Endoscopy encourages you to talk with your healthcare provider about colon cancer screening and encourages everyone over the age of 50 to undergo the appropriate screening. If your primary healthcare provider has recommended a colonoscopy, you can find a physician with specialized training in these GI endoscopic procedures by using the free Find a Doctor tool.

Colon Cancer Screening Saves Lives

Approximately 136,000 new cases of colorectal cancer are diagnosed every year in the United States and nearly 50,000 people die from the disease. It has been estimated that increased awareness and screening would save at least 30,000 lives each year. Colorectal cancer is highly preventable and can be detected by testing even before there are symptoms. The American Society for Gastrointestinal Endoscopy encourages everyone over 50, or those under 50 with a family history or other risk factors, to be screened for colorectal cancer.

This information is intended only to provide general guidance. It does not provide definitive medical advice. It is very important that you consult your doctor about your specific condition.

The Patient Protection and Affordable Care Act

The Patient Protection and Affordable Care Act, passed in 2010, waives the coinsurance and deductible for many colon cancer screening tests, including colonoscopy, sigmoidoscopy and fecal occult blood testing (FOBT). Colonoscopy is a unique screening test because gastroenterologists are able to remove precancerous polyps during the screening procedure. Under Medicare billing rules, removal of any polyp reclassifies the screening colonoscopy as a therapeutic procedure, for which patients will receive a coinsurance bill. This is often unexpected by patients under the impression that deductible or coinsurance charges were waived.

There are efforts ongoing to correct this problem. ASGE, along with the American Cancer Society Cancer Action Network (ACS CAN), and the American Gastroenterological Association (AGA), are advocating that Congress fix this "cost-sharing" problem, which continues to cause confusion for patients and providers. The Removing Barriers to Colorectal Cancer Screening Act of 2012 introduced in March 2012 by Rep. Charlie Dent, R-PA, waives the coinsurance for a screening colonoscopy regardless of whether a polyp or lesion is found. Congressman Dent's bill applies the same rational policy to beneficiary coinsurance. The expectation is that this will eventually be corrected.

Private Insurance

In February 2013, the federal government issued an important clarification on preventive screening benefits under the Affordable Care Act. Patients with private insurance will no longer be liable for cost sharing when a pre-cancerous colon polyp is removed during screening colonoscopy. This ensures colorectal cancer screening is available to privately insured patients at no additional cost, as intended by the new healthcare law. Patients with Medicare coverage must still pay a coinsurance when a polyp is removed as a result of the screening colonoscopy.

Click here for the guidance language provided by the administration. Patients with private insurance should check with their individual providers to learn the details of their coverage and ask about the Affordable Care Act.

For questions about this Web site, contact For questions specifically related to your health and getting screened for colorectal cancer, contact your doctor, or click here to find a doctor in your area.

Colorectal Cancer Screening Tests Covered by Medicare

In 2000, Medicare started paying for colonoscopy for people age 50 and older. Prior to 2000, Medicare only covered the exam for people at high risk or with symptoms. People on Medicare now have more choices for screening tests.

For people on Medicare, this is what is covered:

  • Stool blood test (FOBT or FIT) each year for those 50 and over
  • Flexible sigmoidoscopy (flex-sig) every four years for those 50 and over at average risk
  • Colonoscopy every two years for those at high risk
  • Colonoscopy once every 10 years for those 50 and over at average risk
  • Barium enema with air contrast instead if a doctor believes that it is as good as or better than flex-sig or colonoscopy
  • Virtual colonoscopy is not covered by Medicare as an initial screening test

Colonoscopy is the most commonly utilized screening test for colon cancer since it has a high yield of detecting precancerous polyps and is able to remove them.