The new technology, called the Cologuard sDNA test, works by identifying specific altered DNA in cells shed by pre-cancerous or cancerous polyps into the patient's stool.
If a DNA abnormality is found, a colonoscopy would still be needed to confirm the results, just as happens now after a positive fecal occult blood test (FOBT) result.
To see whether the test was effective, Ahlquist's team tried it out on more than 1,100 frozen stool samples from patients with and without colorectal cancer.
The test was able to detect 85.3 percent of colorectal cancers and 63.8 percent of polyps bigger than 1 centimeter. Polyps this size are considered pre-cancers and most likely to progress to cancer, Ahlquist said.
The sensitivity of the test is much better than what has been seen in other stool screening tests, the ACS' Brooks added. "But, showing that in a small group of samples is very different from demonstrating that in a population where only a small number of individuals are going to have polyps of that size. Then we will know if this is a big step forward," he said.
According to Ahlquist, Cologuard is the first noninvasive test to detect pre-cancerous polyps, he added.
In addition, the test is the only one that is able to identify cancer in all locations throughout the colon, something which other tests either can't or don't do well, Ahlquist said.
One more advantage: patients do not need to do any special preparation before taking the test, something that other tests require, he added.
Ahlquist noted that the test still needs to be refined. "We learned there are still some bugs and we can make the test even better," he said.
Cologuard is not yet available for sale. Clinical trials comparing the test with colonoscopy are slated to start next year. Ahlquist hopes that the test will be approved and available within two years.
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