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FDA Approves First Non-Invasive DNA Screening Test for Colorectal Cancer
The FDA has approved Cologuard (Exact Sciences), 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.
Colorectal cancer primarily affects people 50 years of age 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 U.S., according to the Centers for Disease Control and Prevention (CDC). The CDC estimates that if everyone aged 50 years or older had regular screening tests as recommended, at least 60% of colorectal cancer deaths could be avoided.
Using a stool sample, the Cologuard screening test 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.
The approval of the Cologuard test does not change current practice guidelines for colorectal cancer screening, the FDA said. Stool DNA testing (also called fecal DNA testing) is not currently recommended by the United States Preventive Services Task Force (USPSTF) as a method to screen for colorectal cancer. Among other guidelines, the USPSTF recommends that adults 50 to 75 years old, at average risk for colon cancer, be screened using fecal occult blood testing, sigmoidoscopy, or colonoscopy.
The safety and effectiveness of the Cologuard test were established in a clinical trial that screened 10,023 subjects. The trial compared the performance of Cologuard with that of the fecal immunochemical test (FIT), a commonly used non-invasive screening test that detects blood in the stool. The Cologuard test detected 92% of colorectal cancers and 42% of advanced adenomas in the study population, whereas the FIT test detected 74% of cancers and 24% of advanced adenomas. Cologuard was less accurate than FIT at correctly identifying subjects who were negative for colorectal cancer or advanced adenomas. Cologuard correctly gave a negative screening result for 87% of the study subjects, whereas FIT provided accurate negative screening results for 95% of the study population.
Along with the FDA’s approval, the Centers for Medicare & Medicaid Services (CMS) issued a proposed national coverage determination for the Cologuard test. Cologuard is the first product reviewed through a joint FDA–CMS pilot program known as parallel review, whereby the two agencies concurrently review medical devices to help reduce the time between the FDA’s approval of a device and Medicare coverage. This voluntary pilot program is open to certain premarket approval applications for devices with new technologies and to medical devices that fall within the scope of a Part A or Part B Medicare benefit category and have not been subject to a national coverage determination.
CMS proposes to cover the Cologuard test once every 3 years for Medicare beneficiaries who meet all of the following criteria:
- Age 50 to 85 years
- Asymptomatic (i.e., 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)
- Average risk of developing colorectal cancer (i.e, no personal history of adenomatous polyps, colorectal cancer, or inflammatory bowel disease, including Crohn’s disease and ulcerative colitis; and no family history of colorectal cancers or an adenomatous polyp, familial adenomatous polyposis, or hereditary nonpolyposis colorectal cancer)
Source: FDA; August 11, 2014.