A randomized comparative study of endocrine monotherapy and a combination of estramustine phosphate with the endocrine therapy in patients with untreated stage D prostate cancer

Background. We investigated the clinical efficacy and the prolongation of survival with combination therapy of estramustine phosphate (EMP) and endocrine therapy in untreated patients with progressive prostate cancer. Methods. We randomly divided 57 patients with untreated stage D prostate cancer into two groups, an endocrine monotherapy group and a group receiving combination treatment, consisting of endocrine therapy plus EMP. Treatment was continued until deterioration. Results. There were no significant differences in the improvement rating for subjective/objective symptoms or in progression-free survival between the two groups. However, overall survival was significantly prolonged in the combination therapy group (log-rank test, P = 0.0394; generalized Wilcoxon's test, P = 0.0145). In particular, overall survival was significantly prolonged, compared to that in the endocrine monotherapy group, in patients in the combination therapy group who were less than 74 years old, those with a performance status (PS) of 1 to 3, a pretreatment prostate-specific antigen (PSA) level of more than 20∈ng/ml, moderately or poorly differentiated carcinoma, or a partial response (PR) based on the PSA level 12 weeks after the start of treatment. There was no significant difference in the incidence of side effects between the combination therapy and the endocrine monotherapy groups. Conclusion. A combination of EMP with endocrine therapy may be useful for initial treatment in younger patients (aged 73 or younger) and in patients at high risk of progressive prostate cancer.