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Cologuard, the first stool-based colorectal screening test that detects the presence of red blood cells and DNA mutations that may indicate the presence of certain kinds of abnormal growths that may be cancers such as colon cancer or precursors to cancer, has won approval from the Food and Drug Administration (FDA).

Colorectal cancer primarily affects people age 50 and older, and among cancers that affect both men and women, it is the third most common cancer and the second leading cause of cancer-related death in the United States. Colorectal cancer screening is effective at reducing illness and death related to colon cancer. The Centers for Disease Control and Prevention (CDC) estimates that if everyone age 50 or older had regular screening tests as recommended, at least 60% of colorectal cancer deaths could be avoided.

Colorectal cancer occurs in the colon (large intestine) or rectum (the passageway that connects the colon to the anus). Most colorectal cancers start as abnormal raised or flat tissue growths on the wall of the large intestine or rectum (polyps). Some very large polyps are called advanced adenomas and are more likely than smaller polyps to progress to cancer.

How it works

Using a stool sample, Cologuard detects hemoglobin, a protein molecule that is a component of blood. Cologuard also detects certain mutations associated with colorectal cancer in the DNA of cells shed by advanced adenomas as stool moves through the large intestine and rectum. Patients with positive test results are advised to undergo a diagnostic colonoscopy.

“This approval offers patients and physicians another option to screen for colorectal cancer,” said Alberto Gutierrez, Ph.D., director of the Office of In Vitro Diagnostics and Radiological Health at the FDA’s Center for Devices and Radiological Health. “Fecal blood testing is a well-established screening tool and the clinical data showed that the test detected more cancers than a commonly used fecal occult test.”

Approval of the Cologuard does not change current practice guidelines for colorectal cancer screening. Stool DNA testing (also called “fecal DNA testing”) is not currently recommended as a method to screen for colorectal cancer by the United States Preventive Services Task Force (USPSTF).

Among other guidelines, the USPSTF recommends adults age 50 to 75, at average risk for colon cancer, be screened using fecal occult blood testing, sigmoidoscopy, or colonoscopy.

Medicare coverage possible

The Centers for Medicare & Medicaid Services (CMS) has issued a proposed national coverage determination for Cologuard.

The test would be covered once every three years for Medicare beneficiaries who meet all of the following criteria:

  • age 50 to 85 years,
  • asymptomatic (no signs or symptoms of colorectal disease including but not limited to lower gastrointestinal pain, blood in stool, positive guaiac fecal occult blood test or fecal immunochemical test), and
  • average risk of developing colorectal cancer (no personal history of adenomatous polyps, of colorectal cancer, or inflammatory bowel disease, including Crohn’s Disease and ulcerative colitis; no family history of colorectal cancers or an adenomatous polyp, familial adenomatous polyposis, or hereditary nonpolyposis colorectal cancer).

Cologuard is manufactured by Exact Sciences in Madison, Wis.


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