Frequently Asked Questions

• What is colorectal cancer?
• How does colorectal cancer affect the U.S. population?
• What causes colorectal cancer, and who is at risk of developing it?
• What are the symptoms of colorectal cancer?
• Is there anything I can do to reduce my risk for colorectal cancer?
• What is cancer screening?
• Why should I get screened for colorectal cancer?
• What are the screening tests for colorectal cancer?
• What about testing for colorectal cancer using newer technology?
• How do I know which screening test is right for me?
• Is colorectal cancer screening covered by insurance?
• What are the Medicare Preventive Service benefits for colorectal cancer screening?

What is colorectal cancer?

Cancer is a group of diseases in which there is abnormal and uncontrolled growth of cells in the body. If left untreated, malignant (or cancerous) cells can spread to other parts of the body. "Colorectal" refers to the colon and rectum, which together make up the large intestine. Colorectal cancer can begin anywhere in the large intestine. The majority of colorectal cancers begin as polyps—abnormal growths—inside the colon or rectum that may become cancers over a long period of time.

How does colorectal cancer affect the U.S. population?

Colorectal cancer is the second leading cancer killer in the U.S. In 2005, 141,405 adults were diagnosed with colorectal cancer, and 53,005 adults died of the disease in the United States.^†

What causes colorectal cancer, and who is at risk of developing it?

The exact cause of most colorectal cancers is not yet known. About 75% of colorectal cancers occur in people with no known risk factors. Some conditions that may increase a person's risk of developing colorectal cancer include—

• A personal or family history of colorectal polyps or colorectal cancer.
• Inflammatory bowel disease (ulcerative colitis or Crohn's disease).
• Genetic syndromes such as familial adenomatous polyposis (FAP) or hereditary nonpolyposis colon cancer (HNPCC). (Just 5% of colorectal cancers are linked to these genetic syndromes.)

What are the symptoms of colorectal cancer?

Colorectal cancer starts with few, if any, symptoms. If symptoms are present, they may include—

• Blood in or on the stool.
• A change in bowel habits.
• Stools that are narrower than usual.
• General, unexplained stomach discomfort.
• Unexplained weight loss.

These symptoms can also be associated with many other health conditions. If you have any of these symptoms, discuss them with your doctor. Only your doctor can determine why you're having these symptoms.

Is there anything I can do to reduce my risk for colorectal cancer?

There is strong scientific evidence that having regular screening tests for colorectal cancer beginning at age 50 reduces deaths from colorectal cancer. Screening tests can find precancerous polyps (abnormal growths) in the colon and rectum, and polyps can be removed before they turn into cancer.

Studies have also shown that increased physical activity and maintaining a healthy weight can decrease the risk for colorectal cancer. Evidence is less clear about other ways to prevent colorectal cancer.

Research is underway to determine whether dietary changes may decrease the risk for colorectal cancer. Currently, there is no consensus on the role of diet in preventing colorectal cancer, but medical experts recommend a diet low in animal fats and high in fruits, vegetables, and whole grain products to reduce the risk of other chronic diseases, such as coronary artery disease and diabetes. This diet also may reduce the risk of colorectal cancer. In addition, researchers are examining the role of certain medications and supplements, including aspirin, calcium, vitamin D, and selenium in preventing colorectal cancer.

Overall, the most effective way to reduce your risk of colorectal cancer is by having regular colorectal cancer screening tests beginning at age 50.

What is cancer screening?

Screening is when a test is used to look for a disease before there are any symptoms. Cancer screening tests, including those for colorectal cancer, are effective when they can detect disease early. Detecting disease early can lead to more effective treatment.

Why should I get screened for colorectal cancer?

Screening saves lives. Colorectal cancers almost always develop from precancerous polyps (abnormal growths) in the colon or rectum. Screening tests can find polyps, so they can be removed before they turn into cancer. Screening tests also can find colorectal cancer early, when treatment works best and the chance for a full recovery is very high. Having regular screening tests beginning at age 50 could save your life.

What are the screening tests for colorectal cancer?

Several screening tests can be used to find polyps or colorectal cancer. Each can be used alone. Sometimes they are used in combination with each other. The U.S. Preventive Services Task Force recommends colorectal cancer screening for men and women aged 50–75 using high-sensitivity fecal occult blood testing (FOBT), sigmoidoscopy, or colonoscopy. Talk to your doctor about which test or tests are right for you. The decision to be screened after age 75 should be made on an individual basis. If you are older than 75, ask your doctor if you should be screened.

• High-sensitivity FOBT (stool test): There are two types of FOBT. One uses the chemical guaiac to detect blood. The other, a fecal immunochemical test (FIT), uses antibodies to detect blood in the stool. You receive a test kit from your health care provider. At home, you use a stick or brush to obtain a small amount of stool. You return the test kit to the doctor or a lab, where the stool samples are checked for anything unusual. How often: Once a year.
• Flexible sigmoidoscopy: For this test, the doctor puts a short, thin, flexible, lighted tube into your rectum. The doctor checks for polyps or cancer inside the rectum and lower third of the colon. How often: Every 5 years.
• Colonoscopy: This is similar to flexible sigmoidoscopy, except the doctor uses a longer, thin, flexible, lighted tube to check for polyps or cancer inside the rectum and the entire colon. During the test, the doctor can find and remove most polyps and some cancers. Colonoscopy also is used as a follow-up test if anything unusual is found during one of the other screening tests. How often: Every 10 years.

What about testing for colorectal cancer using newer technology?

Although these tests are not recommended by the U.S. Preventive Services Task Force, they are used in some settings and other groups may recommend them. Many insurance plans don't cover these tests, and if anything unusual is found during the test, you likely will need a follow-up colonoscopy.

• Double-contrast barium enema: You receive an enema with a liquid called barium, followed by an air enema. The barium and air create an outline around your colon, allowing the doctor to see the outline of your colon on an X-ray.
• Virtual colonoscopy: Uses X-rays and computers to produce images of the entire colon which are displayed on a computer screen.
• Stool DNA test: You collect an entire bowel movement and send it to a lab to be checked for cancer cells.

How do I know which screening test is right for me?

Scientific data do not currently suggest that there is a single "best test" for any one person. Each test has advantages and disadvantages. Patients and their doctors are encouraged to discuss the benefits and potential risks associated with each screening option as they decide which test to use and how often to be tested. Which test to use depends on—

• The patient's preferences.
• The patient's medical condition.
• The likelihood that the patient will have the test.
• The resources available for testing and follow-up.

Is colorectal cancer screening covered by insurance?

Most insurance plans help pay for screening tests for people aged 50 or older. Many plans also help pay for screening tests for people younger than 50 who are at increased risk for colorectal cancer. Check with your health insurance provider to determine your colorectal cancer screening benefits.

What are the Medicare Preventive Service benefits for colorectal cancer screening?

People with Medicare who are aged 50 or older are eligible for colorectal cancer screening. There is no minimum age for colonoscopy. For more information about Medicare's coverage related to colorectal cancer screening, call the Centers for Medicare and Medicaid Services at 1-800-MEDICARE (1-800-633-4227) (TTY users should call 1-877-486-2048) or visit the Medicare Web site.

^†U.S. Cancer Statistics Working Group. United States Cancer Statistics: 1999–2005 Incidence and Mortality Web-based Report. Atlanta (GA): Department of Health and Human Services, Centers for Disease Control and Prevention, and National Cancer Institute; 2009. Available at: http://www.cdc.gov/uscs.