A non-invasive test that detects mutated tumor DNA in feces may be a useful method of screening for colorectal cancer, according to new research findings.

In the study, some 4400 average-risk adults age 50 or older were checked for signs of colon cancer using a standard test (Hemoccult II) that detects hidden blood in stool, or the new fecal DNA test, as well as ‘gold standard’ colonoscopy.

Dr. Thomas F. Imperiale at the Indiana University School of Medicine and colleagues compared test results in a randomly selected group of 2500 participants in the study.

The fecal DNA test detected just over half (16 of 31) of all invasive colorectal cancers, the team reports in Thursday’s New England Journal of Medicine.

“The fecal DNA test was better than the Hemoccult II, the current standard non-invasive screening test,” Dr. Imperiale told Reuters Health, noting that the Hemoccult II detected only 4 of the 31 cancers.

Moreover, the fecal DNA test was more than twice as sensitive as the Hemoccult II test for detecting pre-cancerous tumors.

The percentage of false-positive results - that is, positive tests but negative colonoscopy findings - was almost the same with the DNA test and the Hemoccult test.

Imperiale’s team emphasizes, however, that the place of DNA fecal testing in colorectal cancer screening remains to be determined.

Dr. Steven H. Woolf, from the Virginia Commonwealth University in Richmond, agrees, noting in an editorial that while testing stool for DNA is a “potentially smarter strategy” than testing it for hidden blood, numerous questions remain - including affordability.

The price tag for fecal DNA testing is $400 to $800 compared with a cost of $3 to $40 for fecal occult blood testing, he notes.

The current study was funded by grants from EXACT Sciences, Inc., manufacturer of the stool DNA test.

SOURCE: New England Journal of Medicine, December 23, 2004.