The purpose of this study was to evaluate an ultrasensitive PSA assay in prostate cancer patients following radical prostatectomy (RP) to predict long-term biochemical recurrence (BCR)-free survival.
754 men who underwent RP and had an undetectable PSA post-surgery (<0.1 ng/mL) were studied. PSA was measured in banked serum specimens with an ultrasensitive assay (Hybritech PSA, Beckman Coulter Access 2) using a cutoff of 0.01 ng/mL. PSA was also measured in 44 men post-cystoprostatectomy who had no pathological evidence of prostate cancer with the Hybritech assay and with the AccuPSA assay (Quanterix Corporation).
Seventeen percent (n=131) of the 754 men experienced BCR (median: 4.0 years). The 83% of men (n=623) without BCR had a minimum of 5 years of follow-up (median: 11 years). PSA was <0.01 ng/mL in 93.4% of men with no BCR while 30.5% of men with BCR had a PSA ≥ 0.01 ng/mL. On multivariate analysis, postoperative PSA at a 0.01 ng/mL cutoff, pathological stage and Gleason score, and surgical margins were significant independent predictors of BCR risk. Kaplan-Meier estimates for BCR-free mean survival were 15.2 years (95% CI: 14.9-15.6 years) for PSA <0.01 ng/mL and 10.0 years (95% CI: 8.4-11.5 years) for PSA ≥0.01 ng/mL (p<0.0001). BCR-free rates eleven years after surgery were 86.1% (95% CI: 83.2-89.0%) for PSA <0.01 ng/mL and 48.9% (95% CI: 37.5-60.3%) for PSA ≥0.01 ng/mL (p<0.0001). PSA concentrations in 44 men following cystoprostatectomy were all <0.03 ng/mL with 95.4% <0.01 ng/mL.
In men with a PSA <0.1 ng/mL following RP, a ten-fold lower cutoff (0.01 ng/mL) stratified BCR-free survival and was a significant independent predictor of BCR as were pathological features. PSA concentrations in men without pathological evidence of prostate cancer suggests a higher PSA concentration (0.03 ng/mL) in the ultrasensitive range may be needed to define undetectable.
Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.
The Journal of urology 2015 Aug 22 [Epub ahead of print]
Lori J Sokoll, Zhen Zhang, Daniel W Chan, Adam C Reese, Trinity J Bivalacqua, Alan W Partin, Patrick C Walsh
Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD; James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD , Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD , Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD; James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD , James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD , James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD , Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD; James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD , James Buchanan Brady Urological Institute, Johns Hopkins Medical Institutions, Baltimore, MD