Serum BPSA outperforms both total PSA and free PSA as a predictor of prostatic enlargement in men without prostate cancer.
OBJECTIVE
To determine whether the serum concentration of BPSA, a distinct form of free prostate-specific antigen (PSA) enriched in the nodular transition zone (TZ) tissue of benign prostatic hyperplasia (BPH), can predict TZ volume and diagnose BPH-associated prostatic enlargement in patients without prostate cancer.


METHODS
We studied 91 consecutive patients without prostate cancer who underwent a 10-core or greater biopsy of the prostate. The associations between prostate volume, age, International Prostate Symptom Score, and serum concentrations of PSA, free PSA, and BPSA were evaluated by receiver operating characteristic curve and linear and binary logistic regression analyses.


RESULTS
BPSA and free PSA showed stronger correlations with both age (BPSA = 0.38, free PSA = 0.40, PSA = 0.24) and TZ volume (BPSA = 0.67, free PSA = 0.64, PSA = 0.55) than did PSA. The percent free PSA had no statistically significant correlation with TZ volume (P = 0.08). Subtraction of BPSA from free PSA reduced its correlation with TZ volume to below that of PSA (from 0.64 to 0.48). Linear regression analyses showed that, unlike PSA, both BPSA and free PSA displayed an age-independent relationship to TZ volume. The receiver operating characteristic curve (for TZ greater than 30 cm3) and binary logistic regression analyses showed that BPSA (area under the curve = 0.844) outperformed both free PSA (area under the curve = 0.799) and PSA (area under the curve = 0.749) in its ability to predict clinically significant TZ enlargement.


CONCLUSIONS
In patients without prostate cancer, the serum concentration of BPSA displayed an age-independent, log-linear relationship to TZ volume and was a better predictor of prostatic enlargement than either PSA or free PSA. BPSA may also predict clinical parameters of BPH and is under evaluation as a marker of BPH progression and response to therapy.
Canto
Eduardo I
EI
Baylor Prostate Center, Scott Department of Urology, Baylor College of Medicine, Houston, Texas 77030, USA.
Singh
Herb
H
Shariat
Shahrokh F
SF
Lamb
Dolores J
DJ
Mikolajczyk
Stephen D
SD
Linton
Harry J
HJ
Rittenhouse
Harry G
HG
Kadmon
Dov
D
Miles
Brian J
BJ
Slawin
Kevin M
KM
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011467:Prostate / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood*; D011470:Prostatic Hyperplasia / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D011788:Quality of Life; D012372:ROC Curve; D012680:Sensitivity and Specificity
D017430:Prostate-Specific Antigen