Outcomes of androgen deprivation as sole therapy for localized prostate cancer

Abstract

4627 Background: Recent studies indicate increasing use of androgen deprivation (AD) as primary therapy for localized prostate cancer. The utility of this approach is not well known; thus, we sought to characterize the outcomes and determine independent predictors of disease progression with this approach. Methods: The records of all patients with cT1–2, N0, M0 adenocarcinoma of the prostate treated with AD as sole initial therapy at the Portland VA between 1993 and 2000 were reviewed. Age, race, Charlson health index (CHI), family history, PSA, PSA density (PSAD, PSA/prostate volume), digital rectal exam findings, Gleason score, and % of positive biopsy cores at diagnosis were recorded. Outcomes included PSA failure (confirmed with 2 rising PSAs), PSA nadir, bone fractures, local failure, distant failure, and overall survival. Kaplan-Meier method and log rank test (univariate analysis) and stepwise Cox regression (multivariate analysis) were used to estimate time to each end point. Results: 81 patients with a median age of 73 (58 to 84), median CHI of 1, and median PSA of 13.8 ng/ml were followed for a median of 54 months (6 to 115). Rates of endpoints were: local failure = 9.9%, distant failure = 7.4%, bone fractures= 24.7% (18 osteopenic, 2 pathologic), PSA failure = 21.0%, and death = 40.7%. Factors associated with PSA failure by univariate analysis were % positive biopsy cores ≥ 83% (p=0.0008), age < 70 (p= 0.006), Gleason score ≥ 7 (p= 0.015), abnormal DRE (p= 0.025), and PSA nadir ≥ 0.2 ng/ml (p=0.044). The multivariate analysis identified age < 70 (HR= 6.52, 95% CI = 2.29–18.55) and Gleason score ≥ 6 (HR = 4.00, 95% CI = 2.00–12.00) as independent risk factors of PSA failure after AD therapy. Kaplan-Meier estimate of PSA failure at 5 years was 25%±6%. None of the variables were predictive of overall survival. Conclusions: AD therapy resulted in reasonable control of localized prostate cancer; however, younger patients and those with Gleason ≥ 6 cancers were at higher risk for treatment failure. Bone fracture were relatively frequent, perhaps due to prolonged treatment. The efficacy and toxicity of AD for localized prostate cancer requires further study before this modality can be recommended. No significant financial relationships to disclose.