Docetaxel‐based chemotherapy combined with dexamethasone 1 mg daily oral administration for castration‐resistant prostate cancer: Long‐term outcomes

OBJECTIVES: To report long-term outcome survival analysis of docetaxel-based chemotherapy combined with dexamethasone in castration-resistant prostate cancer patients (Japan-Multinational Trial Organization Pca10-01 trial). METHODS: The Japan-Multinational Trial Organization Pca10-01 phase II trial was a multicenter, prospective single-arm, phase II trial both in non-metastatic and metastatic castration-resistant prostate cancer patients that was organized by The Japan-Multinational Trial Organization. Patients received 75 mg/m2 of docetaxel (every 21 days) and 0.5 mg of dexamethasone orally twice a day continuing throughout the treatment period. The primary end-point of this additional analysis was overall survival. Secondary end-points were progression-free survival and safety. RESULTS: Between January 2011 and February 2014, a total of 76 chemotherapy-naive castration-resistant prostate cancer patients were enrolled. The median overall survival time was 42.5 months. The median overall survival time of M1 patients was 40.5 months (M0: not reached). The median progression-free survival time was 13.2 months (M0: 15.7 months and M1: 12.3 months). The multivariate analysis predicting overall survival of M1 patients showed that time to castration-resistant prostate cancer (≥20 months) was an independent parameter (hazard ratio 0.39, P = 0.023). Regarding the safety analysis, 36 out of 74 patients (48.6%) suffered from any grade of adverse events after the protocol treatment, and 18 patients (24.3%) had grade ≥3 adverse events. CONCLUSIONS: Docetaxel-based chemotherapy combined with dexamethasone can achieve excellent survival efficacy not only in M0 castration-resistant prostate cancer patients, but also in M1 castration-resistant prostate cancer patients.