Stool DNA Testing for Colon Cancer

A new type of non-invasive test to check for colon cancer is available now, and may appeal to people who want to be screened, but don’t want to undergo the usual preparation required for a colonoscopy and some other screening tests. Screening means looking for cancer or pre-cancer in people who have no symptoms of the disease.

The FDA approved the DNA stool test, called Cologuard, in August 2014, and the Centers for Medicare & Medicaid Services (CMS) decided in October 2014 to cover it.

A DNA stool test looks for certain gene changes that are sometimes found in colon cancer cells. Like other colon cancer screening tests, it can find some colon cancers early, before symptoms develop, when they’re likely to be easier to treat. Some screening tests can also sometimes find growths called polyps so they can be removed before they turn into cancer. That means screening can sometimes prevent colon cancer altogether.

However, not everybody will meet the criteria for this type of colon screening test, and some people who get the test will still need to follow it up with a colonoscopy.

The Cologuard test

Cologuard is a stool test that can find abnormalities that indicate cancer or polyps. The patient uses a kit at home to collect a stool sample and mail it to a lab for analysis. The test checks for DNA changes that could indicate cancer or pre-cancerous polyps, and also checks for the presence of blood in the stool that can indicate cancer.

No special diet or bowel preparation (no laxatives or enemas) are required for a stool DNA test. However, if the Cologuard test does indicate cancer or pre-cancer, the patient would then need a colonoscopy to confirm it, and possibly to remove any polyps.

Who can benefit from stool DNA testing

The American Cancer Society recommends regular colon cancer screening for most people starting at age 50. People with a family history of the disease or other risk factors should talk with their doctor about beginning screening at a younger age.

The Society’s guidelines list several different tests that can be used to screen for colon cancer, including the stool DNA test. Medicare will cover the Cologuard test if the patient meets certain criteria:

  • Is age 50 to 85 years
  • Has no signs or symptoms of colon cancer
  • Is at average risk for colon cancer (no personal history of pre-cancerous polyps, colon cancer, or inflammatory bowel disease, including Crohn’s Disease and ulcerative colitis; no family history of colon cancer or pre-cancerous polyps; no familial adenomatous polyposis, or hereditary non-polyposis colorectal cancer)

People with private medical insurance will need to call their insurance company directly to find out if the test is covered for them.

The American Cancer Society recommends that people who choose DNA stool testing as their screening method should have the test every 3 years. If the results are positive (indicate a problem), a colonoscopy is needed.

Colon screening saves lives

According to the Centers for Disease Control and Prevention (CDC), about one-third of US adults who should be getting screened for colon cancer aren’t getting screened. Some experts hope that new non-invasive tests like stool DNA tests will encourage more people to get recommended screenings.

If you’re 50 or older, or you have risk factors for colon cancer, talk to your doctor about which test is right for you and get tested as often as recommended.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.


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