Alternative Antiandrogen Therapy with Flutamide in Patients with Castration-Resistant Prostate Cancer : A Single Center Experience We analyzed the clinical effects of flutamide (FLT) as a second-line agent for maximum androgen blockade (MAB) in patients with castration-resistant prostate cancer who received bicalutamide (BCL) as the first-line MAB agent. This study included 44 cases with progressive prostate cancer who had relapsed after first-line MAB, with BCL at 80 mg/day. After checking for antiandrogen withdrawal syndrome (AWS), they were given FLT at 375 mg/day as second-line MAB. A partial response (prostate-specific antigen [PSA] decline ≧50%) and no change (PSA decline of 0-50% or increase ＜25%) by second-line MAB with FLT were achieved in 34.1% (15/44) and 25.0% (11/44), respectively. The median duration of PSA response was 8.2＋/-4.5 months. In multivariate analysis, Gleason score (≦7 vs ≧8), the first-line response (CR vs PR＋NC), and the second-line response (PR＋NC vs PD) were significantly predictive of cause-specific survival from first-line hormonal therapy relapse to cancer death. Our results confirm previous findings that alternative antiandrogen therapy is effective as a second-line hormonal therapy.