The present study was designed to investigate the efficacy of various combinations of chemotherapeutic agents in the treatment of prostatic cancer in a group refractory to antiandrogenic therapy (Group 1) and in a previous untreated group (Group 2). Therapeutic combinations of Estracyt (E) + Peplomycin (P) + Doxorubicin (Do) and P + Do + 5 FU (F) in Group 1 and E + P, Honvan (Ds) + P and E in Group 2 were carried out. The main objectives of this study were estimations of the efficacy of E and P in relation to the refractory cases of Group 1 and the efficacy of the combination E + P, in Group 2. This is the first such prospective, randomized, controlled study to be carried out in Japan in relation to prostatic cancer. The results obtained in the present study indicated that chemotherapeutic regimens including E provide some enhanced efficacy, but that the efficacy with regard to refractory cases is poor (23.1-27.3%), as has been reported of studies conducted in the USA and Europe. With regard to previously untreated cases, the E + P regimen achieved a relatively higher response rate than the other treatments (72.7 vs 44.5 or 50.0%). In the comparison of survival times and survival curves, there were no statistically significant differences among the various treatment subgroups. A comparison of survival curves revealed the interesting finding that the PAP-related response showed a clear correlation to the survival curves of Group 2 patients.