Oncological outcome of docetaxel-based chemotherapy for Japanese men with metastatic castration-resistant prostate cancer

Abstract Objectives To retrospectively review the oncologic outcomes of docetaxel-based chemotherapy in Japanese men with metastatic castration-resistant prostate cancer (mCRPC). Materials and methods This study included 257 consecutive Japanese patients with mCRPC who were treated with docetaxel-based chemotherapy between April 2007 and March 2010. The prognostic significance of several clinicopathologic factors in these patients was analyzed. Results In these 257 patients, the median age and serum value of prostate-specific antigen (PSA) prior to docetaxel-based chemotherapy were 72 years and 43.0 ng/ml, respectively. Of these patients, 64 (24.9%) and 193 (75.1%) received docetaxel as a weekly (30 mg/m2 ) and 3-weekly (70–75 mg/m2 ) regimen, respectively, and estramustine (EM) was administered in combination with docetaxel in 137 (53.3%). PSA decline was observed in 205 patients (79.8%), including 143 (55.6%) achieving PSA decline ≥ 50%. The median progression-free survival and overall survival (OS) were 4.3 and 25.4 months, respectively. Of several factors examined, univariate analysis identified performance status (PS), PSA value, significant clinical pain, bone metastasis, prior treatment with EM, treatment cycle, and PSA response as significant predictors of OS, of which only PS, significant clinical pain, prior treatment with EM, treatment cycle, and PSA response appeared to be independently related to OS on multivariate analysis. Furthermore, there were significant differences in OS according to positive numbers of these 5 independent risk factors. Conclusions Oncologic outcomes in Japanese mCRPC patients receiving docetaxel-based chemotherapy is generally favorable, and the risk stratification presented in this study may contribute to precisely predicting the prognosis of such patients.