Outcomes of salvage prostate cryotherapy stratified by pre-treatment PSA: update from the COLD registry

Abstract

In this study, we evaluate the outcomes of salvage cryotherapy for locally recurrent prostate cancer within the COLD (cryo online data) Registry. Furthermore, we assess the results of salvage cryotherapy (with intermediate follow-up) stratified by pre-treatment prostate-specific antigen (PSA) levels to determine which patients may best be suited for treatment. The COLD registry was developed as a prospective, centrally collected database among patients undergoing salvage cryoablation for locally recurrent prostate cancer following primary prostate radiotherapy with curative intent. Of the patients undergoing salvage cryotherapy (without neoadjuvant hormonal ablative therapy), complete medical records were available in 156 patients, with their mean follow-up being 3.8 years (0.9-12.7 years). The treatment outcomes of salvage cryotherapy were assessed using the Phoenix definition (nadir PSA + 2 ng/ml) of biochemical failure. Of our entire study population, the biochemical disease-free survival (bDFS) rates at 1, 2, and 3 years were 89.0, 73.7, and 66.7%, respectively. Stratification of our patients into two subgroups is based on their pre-treatment total serum PSA values <5 and ≥5 ng/ml, and bDFS rates at 3 years for these two subgroups were 78.3 and 52.9%, respectively. A Kaplan-Meier analysis of bDFS stratified by these same pre-treatment PSA values revealed that the subset of patients with a PSA ≥ 5 ng/ml had statistically significant poorer bDFS rates (P = 0.01). Salvage prostate cryotherapy is a potentially curative local salvage therapy. The importance of early referral when patients have a pre-treatment PSA < 5 ng/ml is essential to optimize treatment outcomes.