Comparison of salvage radical prostatectomy vs. salvage ablation therapy for biopsy-proven radio-recurrent localized prostate cancer.

Introduction: Radiation therapy for prostate cancer is associated with a 15-20% five-year recurrence rate. Patients with recurrence in the prostate only are candidates for salvage local therapies; however, there is no consensus on modality. This study uses registries at Memorial Sloan Kettering Cancer Center (MSKCC) and University of Western Ontario (UWO) to compare the oncologic outcomes of salvage radical prostatectomy (SRP) and salvage ablation (SA).

Methods: A total of 444 patients were available for analysis. Due to intergroup differences, propensity score methodology was used and identified 378 patients with more comparable pre-salvage prostate-specific antigen (PSA), Gleason score, and primary radiation treatment. Patients underwent SRP at MSKCC and SA at UWO.

Results: Of the 378 patients, 48 died of disease, with a 6.0-year median (interquartile range [IQR] 3.0, 9.7) followup among survivors; 88 developed metastases, with a median 4.6-year (IQR 2.3, 7.9) followup among metastasis-free survivors. There was a non-significantly higher rate of cancer-specific (hazard ratio [HR ] 1.02, 95% confidence interval [CI] 0.51, 2.06, p=0.9) and improved metastasis-free survival (HR 0.71, 95% CI 0.44, 1.13, p=0.15) among patients undergoing SA compared to patients undergoing SRP. There were 143 patients who received hormonal therapy, with higher rates of androgen deprivation therapy (ADT) in SA (HR 1.42, 95% CI 0.97, 2.08, p=0.068), although this did not meet conventional levels of significance.

Conclusions: This propensity score analysis of salvage therapy for radio-recurrent prostate cancer identified no statistically significant differences in oncologic outcome between SRP and SA; however, there was evidence of a lower risk of ADT in the cohort undergoing SRP. Given they are both potentially curative therapies, these treatments are viable options for men with clinically localized, radio-recurrent prostate cancer rather than ADT alone. Future research may further elucidate subpopulations that may be more amenable to either SRP or SA.