A stool DNA test is a relatively new approach for colon cancer screening. Instead of looking for blood in the stool (like FIT or guiac FOBT), these tests look for certain DNA mutations caused from cancerous tumors or precancerous polyps. Cells from precancerous and cancerous lesions with these mutations are often shed into the stool, where these tests may be able to detect them, therefore indicating the presence of precancerous polyps or colon cancer.
Because DNA mutations may differ between colon cancers, stool DNA tests typically target multiple markers to achieve high detection rates. Also, because DNA markers may be present in only trace quantities in stool, very sensitive laboratory methods are required. The new stool DNA tests demonstrate high detection rates of early-stage colon cancer. Unlike other noninvasive tests, the new stool DNA tests also can detect precancerous polyps.
In August 2014, the U.S. Food and Drug Administration (FDA) approved Cologuard, the first stool-based colon screening test that detects the presence of blood and altered DNA that may indicate certain kinds of abnormal growths related to colon cancer or precursors to cancer. In a study of 10,000 people of average risk for colon cancer, Cologuard reportedly was able to accurately detect cancer 92% of the time when it was present in an individual’s body. Learn more about this screening method.
In October 2014, the Centers for Medicare & Medicaid Services (CMS) issued its final National Coverage Decision for Cologuard, making it the first FDA-approved stool DNA test for the detection of colon cancer and precancer covered for Medicare patients throughout the country.
For more information about sDNA, please call the Colon Cancer Alliance’s Toll-free Helpline at (877) 422-2030.