The oncological outcomes and risk stratification in docetaxel chemotherapy for castration-resistant prostate cancer

Objective: To clarify the risk factors and develop a refined risk-stratification model to help in the appropriate selection of docetaxel chemotherapy in patients with castration-resistant prostate cancer. Methods: This study included 97 Japanese patients with castration-resistant prostate cancer who were treated with 70-75 mg/m² docetaxel and 10 mg prednisone every 3 or 4 weeks from 2008 to 2013. The oncological outcomes and prognostic significance of clinicopathological factors were analyzed, and significant prognostic factors were used to develop a risk-stratification model. Results: Prostate-specific antigen decline was observed in 75 patients (77.3%), including 43 (44.3%) who achieved a prostate-specific antigen decline of ≥50%. The median progressionfree survival and overall survival were 5.1 and 20.8 months, respectively. Univariate analysis identified performance status, alkaline phosphatase value, visceral metastasis, duration from diagnosis, duration from initiation of hormone treatment and prior treatment with estramustine as significant predictors of overall survival. Among these, alkaline phosphatase value, visceral metastasis and duration from initiation of hormone treatment were independent prognostic factors in multivariate analysis. Furthermore, risk classification according to the number of independent risk factors present effectively stratified survival among docetaxel-treated castrationresistant prostate cancer patients. Conclusions: Oncologic outcomes in Japanese patients with castration-resistant prostate cancer receiving docetaxel chemotherapy were comparable to or slightly better than those in Western populations, and the risk-stratification model developed in this study may help to predict prognosis and contribute to the selection of suitable therapy after castration resistance.