Colorectal Cancer

Colorectal Cancer Questions & Answers

Provided by Centers for Disease Control and Prevention

What is colorectal cancer?
What is screening?
What causes colorectal cancer?
How does colorectal cancer affect the U.S. population?
Who is at risk to develop colorectal cancer?
Is there anything I can do to reduce my risk?
Who should be tested for colorectal cancer?
Why get screened?
What are the symptoms of colorectal cancer?
What are the screening tests for colorectal cancer?
What about testing for colorectal cancer using new technology, such as virtual colonoscopy and stool DNA testing?
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?

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A: Cancer is a disease in which there is an abnormal and uncontrolled growth of cells in the body. "Colorectal" refers to the colon and rectum, which together make up the large intestines.

Colorectal cancer can originate anywhere in the large intestines. The majority of colorectal cancers develop first as polyps, abnormal growths inside the colon or rectum that may become cancerous.

Q: What is screening?

A: Screening is when a test is used to look for a disease before there are any symptoms. Cancer screening tests are effective when they can detect diseases early and lead to more effective treatment or when they can detect disease before it has become cancer and prevent the development of cancer.

Q: What causes colorectal cancer?

A: The exact cause of most colorectal cancers is not yet known, however research has established that approximately 75% of colorectal cancers occur in people with no known risk factors. Risk factors that may increase a person's risk of developing colorectal cancer include:

A personal or family history of colorectal polyps or colorectal cancer, or
Inflammatory bowel disease (Ulcerative colitis or Crohn's disease), or
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.

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

A: Colorectal cancer is the 2nd leading cancer killer in the United States. In 2005, the American Cancer Society estimates that 145,000 people in the U.S. will be diagnosed with colorectal cancer and 56,290 people will die of the disease.

Q: Who is at risk to develop colorectal cancer?

A: Colorectal cancer occurs in men and women of all racial and ethnic groups. Approximately 75% of colorectal cancers occur in people with no known risk factors. Here are other important facts about who is at risk for developing colorectal cancer:

Most colorectal cancers - more than 90% - are diagnosed in people aged 50 years or older. The risk for developing colorectal cancer increases with age.
A family history of colorectal cancer or colorectal polyps increases a person's risk of developing colorectal cancer.
Certain diseases of the intestines, including inflammatory bowel disease (Ulcerative colitis or Crohn's disease), can increase the risk for colorectal cancer.

Q: Is there anything I can do to reduce your risk for colorectal cancer?

A: 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. In this way, colorectal cancer is prevented.

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, however medical experts recommend a diet low in animal fats and high in vegetables, fruits, and whole grain products to reduce the risk of other chronic diseases, such as coronary artery disease and diabetes. It may also reduce the risk of colorectal cancer. In addition to studying dietary changes, researchers are examining the role of certain medications and supplements, including aspirin, calcium, vitamin D and selenium, in preventing colorectal cancer. However, the most effective way to reduce your risk of colorectal cancer is by having colorectal cancer screening tests beginning at age 50.

Q: Who should be tested for colorectal cancer?

A: All men and women aged 50 years or older should be tested routinely for colorectal cancer. Others who are at increased risk should speak to their doctors about earlier or more frequent testing. Those at increased risk are people with

A family history of colorectal cancer or colorectal polyps.
Certain diseases of the intestines, including 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.)

Q: Why Should I Get Screened?

A: Screening saves lives. Having regular screening tests beginning at age 50 could save your life. 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 can also find colorectal cancer early, when treatment works best and the chance for a full recovery is very high.

Q: What are the symptoms of colorectal cancer?

A: Colorectal cancer develops with few, if any, symptoms at first. However, 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
frequent gas, pains, or indigestion
unexplained weight loss
chronic fatigue

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

Q: What are the screening tests for colorectal cancer?

A: Several tests can be used to screen for colorectal cancer. These recommended tests are used alone or in combination with each other

Fecal Occult Blood Test (FOBT) - A test that checks for occult (hidden) blood in the stool. At home, using a small stick from a test kit, you place a small amount of your stool, from three bowel movements in a row, on test cards. You return the cards to your doctor's office or a lab, where they're checked for blood. This test is recommended yearly. (If blood is found, you likely will need a follow-up colonoscopy.)

Flexible Sigmoidoscopy - Before this test, you use a strong laxative and/or enema to cleanse the colon. Flexible sigmoidoscopy is conducted at the doctor's office, a clinic or a hospital. The doctor (or other specially trained health professional) uses a narrow, flexible, lighted tube to look at the inside of the rectum and the lower portion of the colon. During the exam, the doctor may remove some polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every 5 years. (If polyps are found, you will need a follow-up colonoscopy.)

Combination of Fecal Occult Blood Test (FOBT) and Flexible Sigmoidoscopy - Some doctors recommend having both tests to increase the chance of finding polyps (abnormal growths) and cancers. When used in combination with each other, FOBT is recommended yearly and flexible sigmoidoscopy is recommended every 5 years.

Colonoscopy - Before this test, you will take a strong laxative to cleanse the colon. Colonoscopy is conducted in a doctor's office, clinic, or hospital. You are given a sedative to make you more comfortable, while the doctor uses a narrow, flexible, lighted tube to look at the inside of the rectum and the entire colon. (This test is similar to flexible sigmoidoscopy, except the tube used is longer and allows the doctor to see the entire colon.) During the exam, the doctor may remove some polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every 10 years. (Colonoscopy is also used as a follow-up test if anything unusual is found during one of the other screening tests)

Double Contrast Barium Enema - This test is conducted in a radiology center or hospital. Before the test, you use a strong laxative and/or enema to cleanse the colon. This procedure involves taking X-rays of the rectum and colon after you are given an enema with a barium solution, followed by an injection of air. The barium coats the lining of the intestines so that polyps and other abnormalities are visible on the X-ray. (If polyps are found, you will need a follow-up colonoscopy.)

Q: What about testing for colorectal cancer using new technology, such as virtual colonoscopy and stool DNA testing?

A: Although virtual colonoscopy and stool DNA testing are in use in some settings, data are not yet sufficient to support these tests for colorectal cancer screening. Research studies are being conducted to evaluate their effectiveness as screening tests, especially compared to those screening tests already recommended for colorectal cancer.

Computed tomographic (CT) colonography, commonly referred to as virtual colonoscopy, uses multiple CT images to create a 3-dimensional view of the colon. As is the case with traditional colonoscopy, a patient must prepare for virtual colonoscopy by drinking a strong laxative to thoroughly cleanse the colon. Air is pumped into the rectum to expand the rectum and colon. If a polyp or abnormality is found, it cannot be removed during this procedure. A follow-up colonoscopy, using a lighted tube inserted into the rectum and the colon, will be necessary to remove polyps or take tissue samples for further analysis. Because virtual colonoscopy is still considered experimental, most insurance plans do not cover the procedure.

Molecular genetic testing of DNA in stool is a promising technology that may become an option for screening in the future. Meanwhile, another test showing promise for colorectal cancer screening involves genetic, or DNA, testing of stool samples. This technique has not yet been shown to detect pre-cancerous polyps and is still experimental.

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

A: Scientific data do not currently suggest that there is one "best test." 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 the patient should be tested. The Centers for Disease Control and Prevention (CDC) recommends that patients speak with their doctors about getting screened. Which test to use will likely depend on a patient's preferences, his or her medical condition, the likelihood the patient will follow up and have the test, and resources available for testing and follow-up.

Q: Is colorectal cancer screening covered by insurance?

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

Q: What are the Medicare Preventive Service Benefits for colorectal cancer screening?

A: People with Medicare Part B coverage who are age 50 or older are eligible for colorectal cancer screenings. However, in the case of colonoscopy, there is no age limit. For more information about Medicare, call the Centers for Medicare & Medicaid Services at 1-800-MEDICARE (1-800-633-4227) or visit http://www.medicare.gov. For TTY for the hearing impaired, call 1-877-486-2048.