Docetaxel-based therapy with or without estramustine as first-line chemotherapy for castration-resistant prostate cancer: a meta-analysis of four randomized controlled trials.

PURPOSE: To assess the efficacy and toxicity of the addition of estramustine to docetaxel-based chemotherapy for the treatment of castration-resistant prostate cancer.

METHODS: We systematically searched, without language restrictions, for randomized clinical trials that compared docetaxel-based chemotherapy with or without estramustine in patients with histologically proven prostate cancer. The primary end point was overall survival (OS). Secondary endpoints were prostate-specific antigen (PSA) response rate and grade 3 or 4 toxicity. Data was extracted from the studies by 2 independent reviewers. The meta-analysis was performed by Stata version 10.0 software (Stata Corporation, College Station, Texas, USA).

RESULTS: Four randomized clinical trials (totally 400 patients) were eligible. Meta-analysis showed that there was significant improvement in PSA response rate in docetaxel-based therapy with estramustine group, compared with docetaxel-based therapy group (OR = 1.55, 95% CI = 1.10-2.18, P = 0.012). With regard to OS (HR = 0.873, 95% CI = 0.55-1.40, P = 0.572), grade3 or 4 neutropenia (OR = 1.27, 95% CI = 0.61-2.7), anemia (OR = 1.04, 95% CI = 0.07-16.3), thrombocytopenia (OR = 0.87, 95% CI = 0.13-5.7), diarrhea (OR = 2.3, 95% CI = 0.36-14.9), nausea (OR = 1.14, 95% CI = 0.16-8.35), mucositis (OR = 1.66, 95% CI = 0.50-5.52) , and vomiting (OR = 1.53, 95% CI = 0.23-10.3), and there were no significant differences between the two groups.

CONCLUSIONS: This was the first meta-analysis of docetaxel-based therapy with estramustine versus docetaxel-based chemotherapy in the treatment of castration-resistant prostate cancer. Our meta-analysis did not support the addition of estramustine to docetaxel-based chemotherapy for the treatment of castration- resistant prostate cancer, based on no gain in survival.