We compared the clinical efficacy of treatment with a luteinizing hormone-releasing hormone (LH-RH) agonist alone to combined androgen blockade (CAB) with a LH-RH agonist and fiutamide. A total of 66 stage D2 prostate cancer patients were enrolled from Nov. 1992 to Mar. 1996 (n = 30: LH-RH agonist alone, n = 36 CAB). Serum PSA levels after 3 months of treatment and progression-free survival rates (Kaplan-Meier curves) were compared. Results were statistically evaluated by Wilcoxon's text. There were no differences in PSA levels between LH-RH agonist alone and CAB. Progression-free survival rates were longer in the patients treated CAB compared to LH-RH agonist alone (P = 0.041). Furthermore, in patients with poorly differentiated prostate cancers, longer survival rates were also observed with CAB (P = 0.030). However, there were no differences in high EOD (> or = 2) patients between the two treatments (P = 0.652).