CA Cancer J Clin 2001; 51:8
doi: 10.3322/canjclin.51.1.8
© 2001 American Cancer Society
DNA STOOL TEST HAS POTENTIAL TO MAKE COLORECTAL SCREENING A BREEZE
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Looking for altered DNA in feces
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The key to painless, noninvasive, early diagnosis of colorectal cancers and adenomas could be as simple as examining stool samples for DNA alterations, according to a recent report in the journal Gastroenterology (2000;119: 1219-1227).
Altered DNA arises from neoplasms and is shed into the lumen continuously through exfoliation rather than occasionally through blood. Thus, David Ahlquist MD, and his colleagues at the Mayo Clinic surmised that testing stool for DNA might be more reliable than the fecal occult blood test, which misses many cancers and adenomas.
| The long-held goal of a noninvasive, sensitive, and specific fecal screening tool may be within reach.
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The researchers ran a fecal DNA assay panel on frozen stool samples from 22 patients with known colorectal cancer, 11 patients with colorectal adenomas, and 28 non-cancerous controls. They found mutations and/or other DNA changes in the stool samples from 90% of cancer patients, and in 73% of those from adenoma patients. None of the control samples were found to have altered DNA.
Ahlquist noted that some of the patients in this small study had advanced cancers, which may have had increased shedding. He writes that these encouraging data clearly call for larger clinical trials, to see "if these pilot observations hold up, and the testing can be simplified. Then the long-held goal of a noninvasive, sensitive, and specific fecal screening tool may be within reach."
Robert Smith, PhD, director of cancer screening for the American Cancer Society, says the potential for the DNA stool test to evolve into a new, more efficient screening test for colorectal cancer seems very promising. "However, the results are years away, and while more efficient screening tests are in development, the public needs to be reminded that the tests currently available are quite good at detecting colorectal cancer early, when treatment has the greatest probability of being successful," he says. "All adults age 50 and older, and younger individuals at higher risk, should talk with their health care providers about beginning regular screening" (see article on page 38 for more about colorectal screening).
