“Northwestern Medicine debuts new prostate test …”

We’re a tad flummoxed by a media release from Northwestern Medicine in Chicago stating that it is “the first health care provider in the country to offer a new non-invasive blood test for prostate cancer that is nearly three times more accurate than the current standard prostate-specific antigen (PSA) blood test.”

The test referred to in the media release is the Prostate Health Index or phi test, developed by Beckman Coulter and approved by the U.S. Food and Drug Administration (FDA) back in June 2012. Thus, on the one hand, what has Beckman Coulter been doing for most of the past 2 years if the phi test is really this good? On the other hand, why is Northwestern Medicine claiming that this test is “nearly three times more accurate” than a PSA test, when even Beckman Coulter itself has only ever claimed that  this test is “2.5 times more specific in detecting prostate cancer than PSA … in patients with PSA values in the 4-10 ng/mL range”?

In our view, and in the view of at least one authority at Harvard University, the true clinical value the phi test is still to be demonstrated in clinical practice. It does appear, in theory, to be able to cut the need for unnecessary biopsies (perhaps by ~ 30 percent), but to date there is no evidence that it is able to help to differentiate between clinically significant and clinically indolent forms of prostate cancer.

If what Northwestern Medicine is implying is that they are the first center in the country to be able to offer phi test results on site (i.e., without having to send blood samples to Beckman Coulter or another third party laboratory), then perhaps they should be clearer about this.

Although the phi test probably is an improvement over the original PSA tests in identification of risk for prostate cancer, the real degree of that improvement in a practical, day-to-day, clinical setting may be small. The proof of the pudding is going to be in the eating … and not in the media hype. And then there is going to be the question of the cost. Standard PSA testing today comes at a pretty low cost by comparison with most medical tests. We haven’t yet got a clear understanding of what Beckman Coulter or Northwestern Medicine expect to be able to charge for a phi test. Something tells us that it won’t be of the same order of magnitude as a PSA test.

It is worth noting that, although the phi test has been available in Europe since 2010, it has been extremely rare to hear a newly diagnosed European prostate cancer patient report his phi data as opposed to his PSA level  — so rare that we haven’t come across a single occurrence to date.

It should also be noted that we are not aware of any data to suggest that the phi test can be used to improve monitoring of patients after first-line treatment or later lines of treatment. If you think you detect a little skepticism about the positioning of the phi test in the Northwestern Medicine media release, you would be correct.

One Response

  1. I remember contacting Beckman Coulter exactly a year ago, asking if the test was available. Beckman Coulter’s reply stated:

    “The p2PSA/PHI assay will be available in the US sometime in 2013. It is currently not available at any site, including Quest, in the US. … 800-854-3633”

    I have not followed up on it since.

    When will the Prostate Health Index test be available in California? Where will it be available, Quest Diagnostics?

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