EURURO Vol. 72 No. 6

951 1030

. Despite their merits individually and aside from a
limited number of studies comparing PHI and 4KScore, the
merits of one particular biomarker over any other remains
unknown. Thus, while all of these biomarkers appear to
‘‘work’’, it is not known which one works best for which
populations.
Beyond serum- and tissue-based biomarkers, another
key tool in the diagnostic armamentarium that has emerged
in the past few years is magnetic resonance imaging (MRI)
. Whether MRI gives additional or identical information
to these biomarkers remains unclear. Unfortunately,
without comparative data, clinicians are left to use the
test they are most comfortable with, or even resort to using
multiple assays combined with imaging to accomplish the
same end goal, thereby reducing the potential cost-
effectiveness these new tests afford.
We applaud efforts such as these to improve the
detection of prostate cancer in the most clinically optimum
manner. However, how these new biomarkers should be
used is not clear, as the ‘‘gold’’ standard (ie, PSA) against
which it was tested is no longer golden. Many biomarkers
exist today and while all outperform PSA, they are not
widely used for several possible reasons: (1) there are too
many biomarkers, leading to confusion about the best
biomarker; (2) the new biomarkers, while better than PSA,
are still not good enough; and (3) there is a lack of high-
quality comparative effectiveness studies. While we believe
that all three are reasons for the limited use of these
biomarkers in practice, the lack of comparative studies is a
particular major limitation.
Thus, while IsoPSA represents a new and intriguing
option, until well-conducted comparative effectiveness
studies are carried out, the field of prostate cancer biology
will continue in the unfettered pursuit of more novel
biomarkers and the medicine of diagnosing prostate
cancer will be unmethodical in its use of these new tests.
As prostate cancer continues to evolve from a disease of
overdiagnosis and overtreatment, it is important that we
maintain the paradigm of maximizing patient benefit
while minimizing patient harm in the most economic
manner. New tools for optimizing diagnosis, such as
biomarkers and imaging, serve this aim in part; however,
without comparative data, the creation and implementa-
tion of both clinically effective and cost-effective utiliza-
tion parameters among providers will continue to be
elusive.
Conflicts of interest: Stephen J. Freedland serves as a consultant with
stock options for Armune BioScience, the manufacturer of the APIFINY
blood test. Devin N. Patel has nothing to disclose.
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