Thursday, October 13, 2011

An Old Diagnostic Gets the Boot: PSA Testing in Healthy Men is No Longer Recommended

This week, the United States Preventive Services Task Force is due to release its draft recommendation on the use of the Prostate-Specific Antigen (PSA) test in healthy men of all ages.  The PSA test has been a standard tool in urology to assist in the diagnosis of prostate cancer.

Essentially, this recommendation states that the PSA test in healthy men has no clinical benefit, does not save lives, and actually may lead to unnecessary follow up tests and procedures that can have deleterious effects on the patient’s health (see The New York Times article).

These conclusions are based on the results of five well-controlled clinical studies which confirm the general empirical consensus about the PSA test: its lack of specificity and sensitivity result in unacceptable numbers of false positive and false negative tests, respectively.  In particular, false positive tests are particularly troublesome since a positive test will usually lead to a biopsy and treatment that can lead to impotence and/or incontinence.  While those risks of complications are somewhat acceptable for actual prostate cancer patients, they are unacceptable for individual who have misdiagnosed.

This recommendation by the United States Preventive Services Task Force is already producing strong reactions from prostate cancer survivors and advocacy groups.  The idea of shelving the PSA test is unacceptable to those who feel that this diagnostic saved their live.  The truth is that neither the PSA test nor other currently available tests are particularly useful in detecting prostate cancer.  Hence, there is an urgent need to develop, clinically validate, and deploy effective tools for the early detection of prostate cancer in apparently healthy men.  Ironically, the dominance of the PSA test on the market has probably a substantial obstacle to the development of new diagnostic in this field.  Indeed, the protectionism from a segment of the diagnostic industry with financial interest in PSA testing, as well as the difficulty to change medical practices among physicians have probably contributed to the lack of alternative prostate cancer diagnostics.  One can speculate that the new recommendation about PSA testing will open a breach for innovative tools that will actually save lives.

Thierry Sornasse for Integrated Biomarker Strategy

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