Efficacy and safety of docetaxel-based chemotherapy in Japanese men over 80 years old with castration-resistant prostate cancer.

Abstract

e16094 Background: Docetaxel-based chemotherapy is widely used to treat castration-resistant prostate cancer (CRPC). However, its efficacy in elderly males has not yet been fully elucidated. In Japan, the number of elderly CRPC patients continues to increase. Therefore, it is urgently necessary to evaluate the effect of docetaxel-based chemotherapy in elderly Japanese men with CRPC. Methods: Sixty-eight male patients with CRPC who were treated with first-line docetaxel-based chemotherapy in a single institution from 2006 to 2011 were evaluated retrospectively. Results: The median age was 72.4 ± 6.5 years. Ten patients (14.7 %) were ≥ 80 years old (older group), and 58 (85.3 %) were < 80 years old (younger group). All patients received docetaxel at a dose of 75 mg/m2 once every 3 weeks, and prednisolone 10 mg was given every day orally. The prostate-specific antigen (PSA) levels of the older and younger groups before docetaxel-based chemotherapy were 41.2 ± 37.4 ng/ml and 106.5 ± 184.7 ng/ml, respectively (P = 0.273). The PSA doubling times before docetaxel-based chemotherapy were 91.6 ± 92.6 days and 92.5 ± 91.9 days, respectively (P = 0.977). The performance status of the older group was 0 or 1. In the same group, 7 patients (70.0%) achieved a PSA decline of ≥ 30% and 4 patients (40.0%) achieved a PSA decline of ≥ 50%. In the younger group, the PSA decline was ≥ 30% in 37 patients (63.8%) and ≥ 50% in 26 patients (44.8%). The PSA decline rates of ≥ 30% and ≥ 50% were not significantly different between the two groups (p = 0.68 and p = 0.75, respectively). Progression-free survival (PFS) was also not significantly different between the two groups (PFS 5.3 vs. 7.3 months, p = 0.39). The major grade 3–4 toxicities were myelosuppression. Grade 3/4 neutropenia occurred in 80.0% of the older group and 78.0% of the younger group, and Grade 4 neutropenia occurred in 20.0% of the older group and 24.2% of the younger group. There were no significant differences between the two groups (Grade 3/4; p = 0.89, Grade 4; p = 0.79). Conclusions: Docetaxel-based chemotherapy showed a significant effect with a tolerable adverse event rate in elderly Japanese males over 80 years old with castration-resistant prostate cancer.