NADiA ProsVue prostate-specific antigen slope, CAPRA-S, and prostate cancer--specific survival after radical prostatectomy.

OBJECTIVE: To assess whether NADiA ProsVue prostate-specific antigen slope, a prognostic biomarker for identifying men at a reduced risk of clinically recurrent prostate cancer after radical prostatectomy, is prognostic for prostate cancer--specific mortality (PCSM) and other outcomes. MATERIALS AND METHODS: We examined long-term outcome in the cohort of 304 men selected for the ProsVue 510(k) clinical trial. We assessed the prognostic value of a ProsVue result ≤ 2.0 pg/mL/mo and pathologic risk stratified by the Cancer of the Prostate Risk Assessment Postsurgical nomogram for a reduced risk of prostate cancer--specific survival. We also assessed its value for predicting clinical outcome in men given salvage treatment for biochemical recurrence. Efficacy was assessed using univariate and multivariate Cox regression and the Kaplan-Meier analyses. RESULTS: Median (interquartile range) overall survival for the groups of men with a ProsVue slope result ≤ 2.0 and >2.0 pg/mL/mo were 11.0 (9.4-12.9) and 9.2 (4.9-11.6) years, respectively. The ProsVue univariate hazard ratio (95% confidence interval) for PCSM was 20.6 (6.8-62.7), with P <.0001 for a ProsVue result >2.0 pg/mL/mo vs a result ≤ 2.0 pg/mL/mo. The multivariate hazard ratio of ProsVue adjusted by Cancer of the Prostate Risk Assessment Postsurgical nomogram remained significant (16.7 [4.7-58.6]; P <.0001). The inverse of the hazard ratio translates to a 94.0% risk reduction for PCSM for men with a ProsVue result ≤ 2.0 pg/mL/mo. Salvage treatment for biochemical recurrence did not significantly reduce the hazard of clinical recurrence or PCSM; however, this is based on only 18 events. CONCLUSION: A NADiA ProsVue slope result ≤ 2.0 pg/mL/mo was prognostic for a reduced risk of PCSM in men after radical prostatectomy.

NADiA ProsVue prostate-specific antigen slope is an independent prognostic marker for identifying men at reduced risk of clinical recurrence of prostate cancer after radical prostatectomy.

OBJECTIVE: To validate the hypothesis that men displaying serum prostate-specific antigen (PSA) slopes ≤ 2.0 pg/mL/mo after prostatectomy, measured using a new immuno-polymerase chain reaction diagnostic test (NADiA ProsVue), have a reduced risk of clinical recurrence as determined by positive biopsy, imaging findings, or death from prostate cancer. MATERIALS AND METHODS: From 4 clinical sites, we selected a cohort of 304 men who had been followed up for 17.6 years after prostatectomy for clinical recurrence. We assessed the prognostic value of a PSA slope cutpoint of 2.0 pg/mL/mo against established risk factors to identify men at low risk of clinical recurrence using uni- and multivariate Cox proportional hazards regression and Kaplan-Meier analyses. RESULTS: The univariate hazard ratio of a PSA slope >2.0 pg/mL/mo was 18.3 (95% confidence interval 10.6-31.8) compared with a slope ≤ 2.0 pg/mL/mo (P <.0001). The median disease-free survival interval was 4.8 years vs >10 years in the 2 groups (P <.0001). The multivariate hazard ratio for PSA slope with the covariates of preprostatectomy PSA, pathologic stage, and Gleason score was 9.8 (95% confidence interval 5.4-17.8), an 89.8% risk reduction for men with PSA slopes ≤ 2.0 pg/mL/mo (P <.0001). The Gleason score (<7 vs ≥ 7) was the only other significant predictor (hazard ratio 5.4, 95% confidence interval 2.1-13.8, P = .0004). CONCLUSION: Clinical recurrence after radical prostatectomy is difficult to predict using established risk factors. We have demonstrated that a NADiA ProsVue PSA slope of ≤ 2.0 pg/mL/mo after prostatectomy is prognostic for a reduced risk of prostate cancer recurrence and adds predictive power to the established risk factors.

Nucleic acid detection immunoassay for prostate-specific antigen based on immuno-PCR methodology.

BACKGROUND: Serum prostate-specific antigen (PSA) concentrations after radical prostatectomy typically become undetectable with the use of current immunometric assay methods. Despite modern surgical techniques, 15%-30% of prostate cancer patients undergoing radical prostatectomy develop a biochemical recurrence during follow-up. Unfortunately, poor analytical sensitivity of standard PSA assays delays biochemical recurrence detection, and because of day-to-day assay imprecision ultrasensitive PSA assays cannot assess PSA kinetics. We developed an immuno-PCR assay for total PSA that has a limit of quantification >10 times lower than current ultrasensitive assays. METHODS: The 2-site immunometric assay for total PSA employed 2 monoclonal antibodies, one conjugated to a double-stranded DNA label and the other bound to paramagnetic microparticles. After several washing steps, quantification cycles were determined and values were converted to PSA concentrations. We characterized analytical performance and compared accuracy with a commercially available total PSA assay. RESULTS: The limit of quantification was 0.65 ng/L and the assay was linear in the range of 0.25-152.0 ng/L. Total imprecision estimates at PSA concentrations of 3.8, 24.1, and 69.1 ng/L were <15.2%, <9.4%, and <10.6%, respectively. Recovery of supplemented PSA ranged from 87.5% to 119.2% (mean 100.3%). Dilution recovery ranged from 96.4% to 115.3% (mean 102.3%). There was no high-dose hook effect up to 50 000 ng/L of PSA. Comparison with the commercial PSA assay showed a regression slope of 1.06 and a correlation coefficient of 0.996. CONCLUSIONS: The analytical characteristics of the assay support the use of this assay for the accurate and precise measurement of serum PSA, even at sub-nanogram-per-liter concentrations.