Metastatic prostate cancer treated by flutamide versus cyproterone acetate. Final analysis of the "European Organization for Research and Treatment of Cancer" (EORTC) Protocol 30892.

Abstract

This trial was designed to compare the efficacy of Flutamide (FLU) versus Cyproterone acetate (CPA) in men with metastatic prostate cancer and favourable prognostic factors. The primary endpoint of the trial was overall survival, disease specific survival, time to progression and side effects were secondary endpoints. The results pertaining to sexual function were already reported [Br J Cancer 82(2) (2000) 283]. The trial was designed to detect a 50% improvement in median overall survival with 80% power. At the time of the present report, the trial provides 88% power to detect the planned difference of 50% with a 2-sided Logrank test and 80% power to detect a difference of 43% in median survival. 310 patients were randomized to treatment by FLU (250 mg t.i.d. p.o.) or CPA (100 mg t.i.d. p.o.). Of the 310 patients, 12 (3.9%) were ineligible. The baseline characteristics of the two groups were similar except for age which was significantly younger in the CPA group and for the presence of soft tissue metastases which were absent in the FLU group and present in 6 patients in the CPA group. The median follow-up was 8.6 years, 245 patients died, 158 (64.5%) of prostate cancer. There was no significant difference between the treatment arms with respect to overall survival, specific survival nor time to progression. Side effect profiles were studied and found to be more favourable for CPA overall and in particular with respect to gynecomastia, diarrhea and nausea. The trial shows no significant differences in efficacy between Flutamide and CPA monotherapy. The number of patients who died of prostate cancer up to this time is insufficient for a definitive analysis of specific survival. Erectile function and sexual activity are not preserved with FLU but decay slowly with both antiandrogens, toxicity is more pronounced with FLU.