Predictors of outcome using salvage androgen deprivation therapy after radical prostatectomy.

74 Background: Nearly all men that experience recurrence of prostate cancer after radical prostatectomy are placed on salvage androgen deprivation therapy (sADT) in an attempt to control the disease. Yet, little is known regarding the efficacy of the treatment, the therapeutic duration or the predictors of treatment failure. Therefore, we examined our experience with sADT after radical prostatectomy in a cohort of patients with no evidence of systemic disease. Methods: We identified 1,373 patients that were treated with sADT after radical prostatectomy prior to the development of systemic disease. Clinical and pathologic variables predicting systemic progression and cancer death were evaluated using the Kaplan-Meier method and compared using the log rank test. Multivariate Cox proportional hazard regression models were used to analyze the impact of these variables on disease progression and survival. Results: Patients were treated with sADT at a median of 4.2 years after surgery. The median PSA at initiation of sADT was 1.6 ng/mL. The majority (1,234, 90%) of patients had a calculable PSA doubling time prior to the initiation of sADT. 275 patients (20.0%) experienced systemic progression at a median of 3.1 years after the start of sADT. 175 patients (12.7%) died of prostate cancer at a median of 4.7 years after the start of sADT. Factors that predicted disease progression after sADT on multivariate analysis included either neoadjuvant or adjuvant ADT (HR - 2.0, p<0.0001), increasing pathologic Gleason Score (HR - 1.18, p=0.009), increasing pathologic stage (HR - 1.3, p<0.0001), PSA at start of sADT (HR - 1.3, p<0.0001) and PSA doubling time (1.65, p<0.0001). Conclusions: Most men treated with sADT after radical prostatectomy prior to the development of systemic progression experience a lengthy disease-free interval. Multivariate predictors of treatment failure include prior adjuvant or neoadjuvant ADT, pathologic Gleason Score, pathologic stage, PSA level at initiation of sADT and PSA doubling time before sADT. No significant financial relationships to disclose.