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Arlington, VA, December 23, 2004 – The first major
study evaluating a stool DNA test for colorectal cancer published in today’s
issue of the New England Journal of Medicine shows favorable results for the
detection of colorectal cancer compared to traditional fecal occult blood tests – tests
for hidden blood in the stool that patients can do at home. The new test is
not as effective as colonoscopy for detecting either cancer or pre-cancerous
growths.
In this multi-center trial in the United States, a total of 2,507 fully evaluated patients underwent fecal DNA test and colonoscopy. The sensitivity of fecal DNA test was 52 percent and was significantly better than a fecal occult blood test at 13 percent (sensitivity for cancer.) The fecal occult blood tests were performed without rehydration. The sensitivity of the fecal DNA test for advanced adenomas was 15 percent compared to 11 percent for fecal occult blood test.
The study results suggest that a single time fecal DNA test may be better than single time fecal occult blood test for detecting colorectal cancer. Neither test is effective for detecting precancerous polyps. “It would appear based on the results of this single study, and it is always hazardous to draw too many conclusions based on a single study, that fecal DNA testing is superior to the most commonly used fecal occult blood test as a purely non-invasive colorectal cancer screening test,” said Douglas K. Rex, M.D., FACG, Past President of the American College of Gastroenterology and Director of Endoscopy at Indiana University Hospital in Indianapolis.
Dr. Rex added, "We still don't know how it compares to repeated annual testing for fecal occult blood, or to newer more effective tests for blood in the stool."
Based on the results of this study, colonoscopy remains the most effective screening and diagnostic test for colorectal cancer and precancerous polyps. Colonoscopy is the only test that allows both diagnosis and removal of colon polyps in the same session. The fecal DNA test is an appropriate option to consider in patients who are unwilling to undergo colonoscopy or in whom colonoscopy is not feasible. Newer tests for fecal occult blood or fecal occult blood testing with rehydration are also appropriate considerations in this group, and may be more cost-effective than the fecal DNA test.
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