Survival Following Primary Androgen Deprivation Therapy Among Men With Localized Prostate Cancer

CONTEXT: Despite a lack of data, increasing numbers of patients are receiving primary androgen deprivation therapy (PADT) as an alternative to surgery, radiation, or conservative management for the treatment of localized prostate cancer. OBJECTIVE: To evaluate the association between PADT and survival in elderly men with localized prostate cancer. DESIGN, SETTING, AND PATIENTS: A population-based cohort study of 19,271 men aged 66 years or older receiving Medicare who did not receive definitive local therapy for clinical stage T1-T2 prostate cancer. These patients were diagnosed in 1992-2002 within predefined US geographical areas, with follow-up through December 31, 2006, for all-cause mortality and through December 31, 2004, for prostate cancer-specific mortality. Instrumental variable analysis was used to address potential biases associated with unmeasured confounding variables. MAIN OUTCOME MEASURES: Prostate cancer-specific survival and overall survival. RESULTS: Among patients with localized prostate cancer (median age, 77 years), 7867 (41%) received PADT, and 11,404 were treated with conservative management, not including PADT. During the follow-up period, there were 1560 prostate cancer deaths and 11,045 deaths from all causes. Primary androgen deprivation therapy was associated with lower 10-year prostate cancer-specific survival (80.1% vs 82.6%; hazard ratio HR, 1.17; 95% confidence interval CI, 1.03-1.33) and no increase in 10-year overall survival (30.2% vs 30.3%; HR, 1.00; 95% CI, 0.96-1.05) compared with conservative management. However, in a prespecified subset analysis, PADT use in men with poorly differentiated cancer was associated with improved prostate cancer-specific survival (59.8% vs 54.3%; HR, 0.84; 95% CI, 0.70-1.00; P = .049) but not overall survival (17.3% vs 15.3%; HR, 0.92; 95% CI, 0.84-1.01). CONCLUSION: Primary androgen deprivation therapy is not associated with improved survival among the majority of elderly men with localized prostate cancer when compared with conservative management.