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Mayo Clinic offers at-home colon cancer screening test; critics cite concerns

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Minnesota-based Mayo Clinic is offering a new at-home test that its makers claim is a reliable alternative to the dreaded colonoscopy – although critics are raising questions about the costly new "breakthrough" product.

Hospital officials announced Monday they'll be among the first in the U.S. to offer the FDA-approved Cologuard test – a take-home, stool DNA test that its makers claim could "revolutionize" the screening process for colon cancer.

The test, which is available by prescription only, requires people to send stool samples in the mail for laboratory analysis. The sample would then be checked for the presence of red blood cells and DNA mutations. Patients with a positive result would be urged to undergo a colonoscopy.

“Cologuard represents a significant advancement in identifying colorectal cancer at its most treatable stage. We believe offering this new tool will promote patient and community public health and may move more patients to get screened earlier — a critical step in beating this prevalent and preventable cancer,” Vijay Shah, M.D., chair of Mayo Clinic gastroenterology and hepatology, said in a news release.

If detected at an early stage, the five-year survival rate for colon cancer can be greater than 90 percent. However, 23 million Americans between 50 and 75 years old aren't getting screened as recommended by many health officials.

The American Cancer Society notes that a recent report estimated that 136,830 people in the U.S. will be diagnosed with colon cancer, and 50,310 people will die from it in 2014.

“I am hopeful that the test’s efficacy and convenience will result in improved detection and survival rates for colorectal cancer," David Ahlquist, M.D., a Mayo Clinic gastroenterologist and co-inventor of the test, said in a news release.


But some doctors say more research is needed to determine what role at-home tests like Cologuard should play in colon cancer screening.

A colonoscopy is frequently described as the "gold standard" for detecting the cancer. The maker of Cologuard, Wisconsin-based Exact Sciences, says that a study found the product was 92 percent accurate at identifying patients with colon cancer and 69 percent accurate at identifying patients with bowel lesions or polyps that indicate a high risk for cancer.

But put another way, consumers should understand that "both false positives and false negatives do occur," the company acknowledged in a full-page New York Times ad. The company says that up to 13 percent of people tested were incorrectly diagnosed by Cologuard as having potentially cancerous polyps.

As Los Angeles Times business columnist David Lazarus puts it, "Here's the thing, though: Exact Sciences says Cologuard isn't an exact science."

Also, it should be noted that the product study that involved almost 10,000 patients scheduled for colonoscopy was largely supported by Exact Sciences, the medical news publication MedPage Today notes.

MedPage Today also tells its readership of mostly doctors and health care professionals that "though the diagnostic performance is good, this technology is not yet ready to be implemented for population-based screening."

Cost: $600

Doctors from the Mayo Clinic, in partnership with Exact Sciences, are now making the tests available through Mayo's primary care doctors.

Exact Sciences says the tests can cost up to $599 depending on insurance plans – most of which do not yet cover the test.

The Cologuard test website says that because the FDA just approved the new test, "Medicare and most insurance companies do not currently reimburse the costs for Cologuard." Exact Sciences is currently seeking to have Cologuard included in public and private insurance plans and suggests individuals contact their insurance to see if Cologuard is covered, the website says.

The Associated Press notes that an editorial by two Department of Veterans Affairs doctors mentioned the cost concern in a recent issue of the New England Journal of Medicine.

"Only through a better understanding of other key factors, such as the screening interval, adherence, cost and diagnostic evaluation of positive results, can we determine the appropriate place for stool DNA testing on the screening menu," Dr. Douglas Robertson and Dr. Jason Dominitz wrote in the editorial.

Exact Sciences' stock hit a new peak of $21.45 in early trading Monday, and ended the day at $21.04 a share, up 4 percent from Friday.

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