Population based study of hormonal therapy and survival in men with metastatic prostate cancer

PURPOSE: Although the palliative benefits of hormonal therapy for metastatic prostate cancer are widely recognized, little information is available regarding the effect of hormonal therapy on cancer specific and overall survival, and the types of patients who might benefit the most or least from hormonal therapy. MATERIALS AND METHODS: Prostate cancer specific and overall survival according to hormonal therapy use was determined by the Kaplan-Meier method in 6,098 men 65 years or older diagnosed with metastatic prostate cancer in 1991 to 1999 who were identified through the population based Surveillance, Epidemiology, and End Results, and Medicare linked database. Cox proportional hazards and propensity score methods were used to adjust for potential confounders, such as disease status and patient comorbidity. RESULTS: Propensity score adjusted median overall survival was 26 months in men who received hormonal therapy compared with 13 months in those who did not (HR 0.66, 95% CI 0.17-0.70, p <0.0001). The benefit of hormonal therapy was observed across all comorbidity strata and races. Effects were most evident in patients with poorly differentiated cancer (cancer specific mortality in favor of treatment HR 0.60, 95% CI 0.53-0.69, p <0.001). Benefit was not found in patients with well differentiated cancer (cancer specific mortality in favor of no treatment HR 1.92, 95% CI 0.90-4.10, p = 0.09). CONCLUSIONS: Hormonal therapy is associated with improved prostate cancer specific and overall survival in men with poorly differentiated cancer. Improved survival does not appear evident in men with well differentiated disease.