Abstract
Background
Novel markers for prostate cancer (PCa) detection are needed. Total prostate-specific
antigen (tPSA) and percent free prostate-specific antigen (%fPSA = tPSA/fPSA) lack diagnostic specificity.
Objective
To evaluate the use of prostate-specific antigen (PSA) isoforms p2PSA and benign prostatic
hyperplasia–associated PSA (BPHA).
Design, setting, and participants
Our study included 405 serum samples from the Rotterdam arm of the European Randomised
Study of Screening for Prostate Cancer and 351 samples from the Urology Department
of Innsbruck Medical University.
Measurements
BPHA, tPSA, fPSA, and p2PSA levels were measured by Beckman-Coulter Access Immunoassay.
In addition, the Beckman Coulter Prostate Health Index was calculated: phi = (p2PSA/fPSA) × √(tPSA).
Results and limitations
The p2PSA and phi levels differed significantly between men with and without PCa.
No difference in BPHA levels was observed. The highest PCa predictive value in both
cohorts was achieved by phi with areas under the curve (AUCs) of 0.750 and 0.709,
a significant increase compared to tPSA (AUC: 0.585 and 0.534) and %fPSA (AUC: 0.675
and 0.576). Also, %p2PSA (p2PSA/fPSA) showed significantly higher AUCs compared to
tPSA and %fPSA (AUC: 0.716 and 0.695, respectively). At 95% and 90% sensitivity, the
specificities of phi were 23% and 31% compared to 10% and 8% for tPSA, respectively.
In both cohorts, multivariate analysis showed a significant increase in PCa predictive
value after addition of p2PSA to a model consisting of tPSA and fPSA (increase in
AUC from 0.675 to 0.755 and from 0.581 to 0.697, respectively). Additionally, the
specificity at 95% sensitivity increased from 8% to 24% and 7% to 23%, respectively.
Furthermore, %p2PSA, phi, and the model consisting of tPSA and fPSA with or without
the addition of p2PSA missed the least of the tumours with a biopsy or pathologic
Gleason score ≥7 at 95% and 90% sensitivity.
Conclusions
This study shows significant increases in PCa predictive value and specificity of
phi and %p2PSA compared to tPSA and %fPSA. p2PSA has limited additional value in identifying
aggressive PCa (Gleason score ≥7).
Keywords
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Article Info
Publication History
Published online: February 15, 2010
Accepted:
February 3,
2010
Received:
October 27,
2009
Footnotes
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Identification
Copyright
© 2010 European Association of Urology. Published by Elsevier Inc. All rights reserved.
