Can docetaxel therapy improve overall survival from primary therapy compared with androgen-deprivation therapy alone in Japanese patients with castration-resistant prostate cancer? A multi-institutional cooperative study

Background To verify the actual clinical benefit of docetaxel (DOC) therapy and to explore the prognostic factors that may predict overall survival in Japanese patients with castration-resistant prostate cancer (CRPC). Methods Baseline characteristics-matched CRPC patients who received conventional androgen-deprivation therapy (ADT) or ADT plus DOC were compared retrospectively. The primary endpoint was overall survival (OS) from primary therapy. Secondary endpoints were response of tumor(s), prostate-specific antigen (PSA) levels, and toxicity. Results Median OS was significantly longer in the DOC group ( n = 117) than the control group ( n = 118) (94.0 vs. 70.0 months, P = 0.0077) and the corresponding hazard ratio (HR) for death in DOC group was 0.566 [95% confidence interval (95%CI) 0.370–0.867; P = 0.0088]. Effective DOC groups [medium dose (50–69 mg/m 2 ) and high dose (≥70 mg/m 2 )] had significantly longer median OS than control even when survival times were calculated from the start of castration-resistant events (151 vs. 36 months; P = 0.0173) and the corresponding HR for death in the DOC group was 0.515 (95%CI 0.293–0.903; P = 0.0205). In multivariate analysis, statistically significant prognostic indicators were Gleason score, time to CRPC events, and receipt of DOC therapy. Response rate of both measurable lesion and PSA was not significantly different between each DOC dose group. Grade 3 or 4 adverse events associated with low- [30–49 mg/m 2 ], medium-, and high-dose DOC were 21.9, 35.7, and 90.7%, respectively. No death due to DOC therapy was reported. Conclusion Treatment with DOC improves OS from primary therapy compared with conventional ADT alone in Japanese patients with CRPC.