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
Thierry Sornasse for Integrated Biomarker Strategy
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