Abstract
BACKGROUND: Primary androgen deprivation therapy (PADT) is frequently used as a sole modality of treatment in men with localized prostate cancer, despite a lack of clinical trial data supporting its use. OBJECTIVE: To measure the impact of treatment with PADT compared to observation on overall survival in men with organ-confined prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: The design was for an observational cohort from Surveillance, Epidemiology, and End Results (SEER) Medicare data. The cohort consisted of 16,535 men aged 65-80 yr at diagnosis with organ-confined well-differentiated or moderately differentiated prostate cancer who survived >1 yr past diagnosis and did not undergo treatment with prostatectomy or radiation therapy within 6 mo of diagnosis. They were diagnosed between 1991 and 1999 and followed until death or until the end of the study period (December 31, 2002). INTERVENTION: Study subjects were selected to receive PADT alone if they received luteinizing hormone-releasing hormone agonists or bilateral orchiectomy in the first 6 mo after diagnosis, and they were selected to be observed if they did not have claims for PADT during the same interval. MEASUREMENTS: Overall survival. RESULTS AND LIMITATIONS: After adjusting for potential confounders (ie, tumor characteristics, comorbidities, and demographics), patients who received ADT had a worse overall survival rate than patients who were observed (hazard ratio: 1.20; 95% confidence interval: 1.13-1.27). In observational studies there may be unmeasured differences between the treated and untreated groups. The SEER database does not provide information on prostate-specific antigen levels. CONCLUSIONS: This large, population-based study suggests that PADT did not improve survival in men with localized prostate cancer, but it suggests that PADT may instead result in worse outcomes compared with observation. Patients and physicians should be cognizant of the potential long-term side effects of ADT in a patient population for which expectant observation is an acceptable treatment strategy.