Los Angeles Times business/consumer columnist David Lazarus writes, “A good alternative to having a colonoscopy? Maybe not.” Excerpt:
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.
That’s just a taste of the Lazarus column. Read the entire piece.
That kind of scrutiny was missing in most stories we saw two weeks ago when the FDA approved the Cologuard test. At that time, Dr. James Allison, an emeritus UC-San Francisco prof and gastroenterologist, wrote to me:
It is important for reporters to understand that the following about the stool DNA test just approved by the FDA.
1. The old test (fecal immunochemical test for hemoglobin or FIT) is not a class. Because a new test is better than a FIT doesnt mean it is better than all or even the same one with two samples or a cut off for a positive test that is lower than the one the EXACT test was compared with.
2. There is no evidence that a 3 year interval between EXACT tests is safe. That evidence must come before an interval greater than every year is approved. FIT in the U.S. are recommended every year (as was done for the less sensitive stool guaiac test) instead of every 2 years as in Europe and Asia. This will probably change in the U.S. in the next year or so as new guidelines come out but only because of evidence in multiple studies that an every 2 year interval is safe.
3. A very important component of the EXACT stool DNA test is the old test i.e. a FIT. The EXACT test is a multimarker test and one of the markers is blood.
4. When discussing a new test you must also talk about the negatives. In this case they are:
a. Decrease in specificity compared to FIT
b. Markedly increased cost compared to FIT
c. Requirement for large samples to be collected by patients for sufficient material to test.
The EXACT test is an important addition to our screening for the colorectal cancer armamentarium but it is unlikely to be a game changer.
So, you see, coverage of screening tests and of new technologies would benefit from much more scrutiny. As journalist Lazarus wrote:
“with each new, state-of-the-art test that comes along, America’s nearly $3 trillion in annual healthcare spending creeps ever higher. This country already pays about twice per person on average than all other developed countries.”
ADDENDUM on August 27:
Meantime, see the Star Tribune story, “Mayo offers at-home colon cancer test.”
And then see reader Ron Way’s letter to the editor, which states:
Cologuard test isnt just a Mayo product
The Star Tribunes front page (Aug. 26) trumpeted that Mayo Clinic will be first in the nation to offer a self-screening cancer test with a product called Cologuard, which, the story said, is available through Mayos primary-care doctors by prescription.
However, those a of cancer-vulnerable age need not travel to Rochester for the test, as the story implies; Cologuards website says the kit is available through any doctor enrolled by the companys lab in a process thats very simple and easy.
The story also reported that a Mayo doctor is co-inventor of Cologuard. But it didnt report that under a license agreement with Exact Sciences in Madison, Wis., the doctor and Mayo share in equity and royalties for the test kit.
Mayo is a fine and respected clinic, but there are many quality primary-care doctors and centers far closer to interested patients that, unlike Mayo, dont have a direct revenue motive for prescribing Cologuard.
Ron Way, Edina
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