5-Year Biochemical Progression-Free Survival Following Salvage Whole-Gland Prostate Cryoablation: Defining Success with Nadir PSA.

BACKGROUND & OBJECTIVES - Salvage prostate cryoablation is an effective treatment for patients with localized prostate cancer relapse following primary radiotherapy. The post-salvage PSA nadir that best predicts long-term biochemical progression-free survival (bPFS) is not yet defined.

We sought to determine what nadir PSA best predicted success following salvage whole-gland cryoablation.

METHODS - We retrospectively reviewed a cohort of 486 hormone naive patients who underwent salvage whole-gland cryoablation from the Cryo On-Line Database (COLD). Studied variables were age, race, initial PSA, pre-salvage PSA (psPSA), initial Gleason score, Gleason score at pre-salvage biopsy, clinical stage and follow up PSA values. Kaplan-Meier (KM) analysis was used to calculate five-year bPFS using the Phoenix criteria. Hazard ratio (HR) and relative risk (RR) were also analyzed. Differences among the KM estimates, at five-years, were calculated using the log-rank test.

RESULTS - Using group thresholds, KM analysis identified nadir PSA< or > 0.4 ng/ml as the nadir PSA threshold with the greatest difference in bPFS. The KM estimated five-year bPFS was 75.5% and 22.1% for nadir PSA <0.4ng/ml and nadir PSA ≥0.4 ng/ml, respectively. Stratified by psPSA, the KM estimated five-year bPFS comparing patients with PSA nadir 10ng/ml, respectively.

CONCLUSIONS - The best objective indicator of biochemical success following whole-gland salvage cryoablation of the prostate is PSA nadir < 0.4 ng/ml.

Journal of endourology / Endourological Society. 2016 Feb 26 [Epub ahead of print]

Evan Kovac, Ahmad Elshafei, Kae Jack Tay, Melissa Heuer Mendez, Thomas Polascik, J Stephen Jones

The Cleveland Clinic, Glickman Urological & Kidney Institute, Cleveland, Ohio, United States ; The Cleveland Clinic, Glickman Urological & Kidney Institute, Cleveland, Ohio, United States., Duke University Medical Center, Urology, Durham, North Carolina, United States ; Duke University Medical Center, Urology, Durham, North Carolina, United States ;  Duke University Medical Center, Urology, Durham, North Carolina, United States ;  The Cleveland Clinic, Glickman Urological & Kidney Institute, Cleveland, Ohio, United States ;