Factors influencing prostate cancer specific mortality in patients receiving delayed androgen deprivation therapy for metastasis after biochemical recurrence following radical prostatectomy

Abstract

4571 Background: For men developing PSA failure after radical prostatectomy (RP), administration of immediate androgen deprivation therapy (ADT) has not been shown to improve survival compared to delaying ADT until evidence of metastatic disease. We evaluated factors influencing prostate cancer (PCa) specific mortality (PCSM) in a cohort of PSA era patients developing metastases after RP treated with delayed ADT. Methods: 3,658 men had RP by a single surgeon at Johns Hopkins Hospital from 4/82 until 6/05. 553 had PSA failure. 216 developed radiographically evident distant metastasis. Of these, 91 men formed the study cohort: initially treated during the PSA era (1987–2005), received ADT only after documented metastasis, and having complete data. 41 of these men died. Median failure times were estimated with the Kaplan-Meier method. Prognostic impact was estimated as the hazard ratio (HR) derived from the Cox proportional hazards model. Results: Median followup from RP was 10 yrs (range 2–18). Actuarial median failure times are: 1 yr from RP to PSA failure (range 1–11), 32 mos from PSA failure to metastasis (range 0–129), 79 mos from metastasis to death (range 7–181), and 13 yrs from RP to death (range 2–18). The following variables were significant prognostic factors for PCSM in univariate analyses: Pain at diagnosis of metastases (p < 0.01), time from RP to metastasis (p = 0.02), hematocrit at metastasis (p < 0.01) and PSADT <3 mos during the 2 years prior to metastasis (p < 0.01). A multivariable Cox proportional hazards model demonstrated the following independent predictors of PCSM: pain (HR = 10.5 p < 0.01), PSA at metastasis ≥100 ng/mL (HR = 5.3 p < 0.01) and PSADT < 3 months (HR = 7.1 p < 0.01). PSADT determined in the two years immediately after PSA failure (HR = 1.0 p = 0.37) and time from RP to bone metastasis (HR = 1.0 p = 0.80) were not independent predictors of PCSM. Conclusion: Men receiving delayed ADT for development of metastasis after RP may have a prolonged survival time (13 yrs post RP - range 2–18). Optimizing the time for ADT in these patients requires well-designed, prospective randomized studies. Our data may facilitate the selection of patients and thresholds for implementation of ADT. No significant financial relationships to disclose.