Does prolonged combined androgen blockade have survival benefits over short-term combined androgen blockade therapy?

Objectives. To explore whether less than 120 days of an antiandrogen plus a luteinizing hormone-releasing hormone agonist resulted in a different surv ival outcome than 120 days or more of combined treatment in patients with S tage D2 prostate cancer. Methods. Survival data were available from a previously published controlle d trial that had evaluated the efficacy and tolerability of two antiandroge ns, bicalutamide and flutamide, each combined with a monthly depot preparat ion of leuprolide or goserelin, in 813 patients with Stage D2 prostate canc er. Cox's proportional hazards regression model assessed the relative effec ts of the length of combined androgen blockade (CAB) therapy on survival. T his analysis was repeated in the subset of patients who lived at least 2 ye ars beyond the date of randomization. Data were obtained at a median follow -up of 160 weeks. Results. A survival benefit was demonstrated for patients receiving prolong ed CAB therapy, with a hazard ratio of 0.275 (95% confidence interval 0.213 to 0.355, P = 0.0001) in favor of patients who received 120 days or more o f CAB therapy (median survival 1035 days versus 302 days for less than 120 days of therapy). This result was confirmed in the patients who lived at le ast 2 years, in whom the median survival time was increased by 55%. The haz ard ratio for 120 days or more of CAB therapy Versus less than 120 days was 0.415 (95% confidence interval 0.246 to 0.702, P = 0.001). Conclusions. The results of the present exploratory analysis suggest that p rolonged (120 days or more) antiandrogen treatment as part of CAB therapy m ay result in a better survival outcome. (C) 2000, Elsevier Science Inc.