A good alternative to having a colonoscopy? Maybe not

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Is Cologuard a good alternative to colonoscopy?

Cologuard is the first FDA-approved, non-invasive, stool-based DNA colorectal cancer screening test. (Exact Sciences / June 18, 2014)

There are few medical tests with as high a squirm factor as colonoscopies.

So anyone who comes along with a simple, non-invasive alternative is probably going to make a lot of money.

If the alternative test is any good.

A Wisconsin company called Exact Sciences has launched a marketing campaign for its new product, Cologuard, which it hails as "the breakthrough test for colon cancer screening that's as easy as going to the bathroom."

Although stool tests have been around for a while, Cologuard is the first to use a person's DNA, rather than blood, to spot tumors. It was approved this month by the Food and Drug Administration.

Here's the thing, though: Exact Sciences says Cologuard isn't an exact science.

In a full-page ad that ran this week in the New York Times, the company said that while the test can detect 92% of colon cancers, "both false positives and false negatives do occur."

It said that up to 13% of people tested were incorrectly diagnosed by Cologuard as having potentially cancerous polyps. The rate of false positives for blood-based stool tests is no higher than 5%, researchers say.

Exact Sciences' ad said that anyone testing positive with Cologuard should confirm the result with a colonoscopy. It also said that anyone testing negative should still be regularly screened "with a method appropriate for the individual patient," which in many cases means a colonoscopy.

This raises questions about the value of this "breakthrough test," which Exact Sciences is pricing at about $600 per patient — compared with $25 for the traditional stool blood exam — and which, because of its newness, isn't yet covered by any private insurance plans.

It also highlights, once again, the trend of drug and medical companies spending billions of dollars to market directly to consumers. The United States and New Zealand are the only developed countries that allow this practice.

Dr. Joel Lavine, chief of gastroenterology, hepatology and nutrition at New York's Columbia University Medical Center, told me that there's significant benefit in having a colon cancer test "for patients who either can't or won't undergo colonoscopy or sedation."

Cancer of the colon and rectum is the second-leading cause of U.S. cancer deaths, according to the Centers for Disease Control and Prevention. More than 50,000 people in this country die from colorectal cancer annually.

All people over the age of 50 are encouraged by healthcare practitioners and organizations to have a colonoscopy every 10 years.

Lavine said the 13% rate of Cologuard false positives "could be concerning," but these concerns can be mitigated "with more definitive colonoscopy tests."

Dr. Bennett Roth, a professor of gastroenterology at UCLA, took a more measured approach to Cologuard. He said the test is still a work in progress, "but it's a move in the right direction."

Cologuard's greatest benefit, Roth said, is that it could encourage more people to have a colonoscopy, which remains the gold standard for diagnosing and treating colon cancer.

"Maybe if you get a positive test with Cologuard, you'd be convinced to have the more definitive test," he said. "It doesn't replace the need for a colonoscopy."

Nor is Exact Sciences saying that.

"Nobody is arguing that a colonoscopy isn't a great way to get screened," said Kevin Conroy, the company's chief executive. "Our mission is to get more people screened."

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