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It's ALL THINGS CONSIDERED from NPR News. I'm Audie Cornish. Colon cancer is the second deadliest cancer in the U.S. behind lung cancer and scientists are trying to make it easier to spot. Several new tests that use DNA samples could do that.
A Mayo Clinic doctor came up with one of them after he went to rural Alaska. He realized people in remote areas have trouble just getting screened. Alaska Public Radio Network's Annie Feidt reports.
ANNIE FEIDT, BYLINE: When Mayo Clinic Dr. David Ahlquist took a trip to Bethel in western Alaska in the mid-1990s, a startling statistic came to his attention. Alaska natives were and still are twice as likely to get colon cancer and die from the disease as Caucasian Americans.
DAVID AHLQUIST: Here, they had one of the world's highest rates of colon cancer and one of the world's poorest outcomes in terms of survival from cancer because of late diagnosis.
FEIDT: He realized traditional screening methods had flaws in places like rural Alaska. Colonoscopy equipment isn't available in remote native villages and a widely used test that detects blood in stool isn't effective because many Alaska natives have stomach bacteria called H-pylori that also cause bleeding. The colon cancer screening rate for Alaska natives in some rural areas of the state is as low as 23 percent.
So, when he returned to the Mayo Clinic, Ahlquist began working on a new kind of test. He wanted it to be highly accurate, accessible to anyone and easy to use. The test he eventually developed can identify several altered genes that are only present in colon cancer.
AHLQUIST: It measures DNA changes that are shed from the surface of cancer or pre-cancers into the stool and we can detect those changes that act as a signature of the presence of cancer or polyps.
FEIDT: According to two studies published this year, the DNA test finds 85 percent of colon cancers and more than 50 percent of pre-cancerous polyps. Ahlquist and the Mayo Clinic are working with a company called Exact Sciences to commercially develop the test and both will benefit financially if it comes on the market.
Ahlquist says the test could represent a revolution for colon cancer screening, much like the pap smear did for cervical cancer half a century ago.
AHLQUIST: The pap smear took a target, cervical cancer, which, in the '50s, was the number one cancer killer in the United States among women. Now, in those women who are screened with the pap smear, it's a rare disease. It's essentially been eradicated in women who are screened.
FEIDT: That may sound like a bold claim, but it's one that has merit, according to Dr. Randall Burt, director of prevention at the Huntsman Cancer Institute in Utah.
RANDALL BURT: Well, in the end, it could be a huge game changer.
FEIDT: Burt has been watching the development of the colon cancer test over the years as an outside observer and he thinks it's fair to say the DNA test could one day be compared to the pap smear, especially if it gets better at detecting pre-cancerous polyps.
BURT: Is it enough to replace colonoscopies so that we only do colonoscopy on people with a positive stool test? Probably not yet, but it's getting there.
FEIDT: In anticipation of FDA approval early next year, the DNA test is undergoing a trial at more than 100 sites in the U.S. and Canada. There's no guarantee it will pass that final hurdle and Burt says it's important for the test to prove itself in that more rigorous study.
In Alaska, there's hope Ahlquist's colon cancer DNA test could help make the disease less deadly. In February, the Alaska Native Tribal Health Consortium began a three-year trial of the test. One hundred patients have enrolled so far.
Janet Kelly is cancer surveillance director at ANTHC. She says the test holds a lot of promise for Alaska natives.
JANET KELLY: Until we can find a cure for this cancer, the best we have is to screen and early detection is - through this test, offers a lot of opportunity.
FEIDT: It's expected to cost about $300, far less than the average colonoscopy in Alaska. It could be available as soon as the middle of next year.
For NPR News, I'm Annie Feidt in Anchorage.
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