Purpose: The outcome of patients with symptomatic metastatic prostate cancer is poor and improved treatment regimens are urgently needed. Theoretically, the combination of orchiectomy and chemotherapy could reduce androgen sensitive and insensitive cells in the prostate. This European Organization for Research in Cancer Therapy Genitourinary Group randomized, multicenter phase III trial demonstrates the outcome of orchiectomy alone versus orchiectomy followed by intravenous mitomycin C.
Materials and methods: A total of 189 patients with metastatic prostate cancer and poor prognostic factors were randomized in this trial by 42 institutions. Of these patients 184 (97%) were eligible for study, including 90 treated with orchiectomy alone (orchiectomy only arm) and 94 treated with orchiectomy followed by 15 mg./m.2 mitomycin C in 1 week (combined treatment arm). Mitomycin C was administered every 6 weeks and treatment was continued as long as tolerance and patient compliance allowed, and no progression was observed. Objective and subjective criteria for progression were clearly defined in the protocol.
Results: Patient and tumor characteristics were well balanced between the 2 treatment arms. At a median followup of 4.2 years 144 patients had died, including 112 of prostate cancer. No significant differences for time to overall (p = 0.17), subjective (p = 0.25) and objective (p = 0.08) progression were found between the 2 treatment groups. For progression-free survival no difference was noted (p = 0.67) between the 2 treatment groups but a trend in favor of orchiectomy alone was observed for overall survival (p = 0.04). Mitomycin C induced considerable hematological, gastrointestinal, renal and pulmonary toxicity leading to discontinuation in 31% of patients with pulmonary toxicity and 7% with renal deterioration. In addition, the quality of life evaluation revealed significant reduction in the combined treatment arm.
Conclusions: Based on the results of this randomized phase III study orchiectomy plus mitomycin C for metastatic prostate cancer in patients with poor prognostic factors cannot be recommended due to failure of improvement in survival and reduced quality of life parameters.