Significance of docetaxel-based chemotherapy as treatment for metastatic castration-resistant prostate cancer in Japanese men over 75 years old.

OBJECTIVES

The objective of this study was to evaluate the significance of docetaxel-based chemotherapy in elderly Japanese men with metastatic castration-resistant prostate cancer (CRPC).

MATERIALS AND METHODS

This study included a total of 159 consecutive patients aged≥75 years with mCRPC who were treated with docetaxel-based chemotherapy. The efficacy and tolerability of this therapy were retrospectively analyzed.

RESULTS

In these 159 patients, the median age and prostate-specific antigen (PSA) level before docetaxel-based chemotherapy were 78 years and 44.0 ng/ml, respectively. Of these patients, 42 (26.4%) and 117 (73.6%) received docetaxel as a weekly (30 mg/m2) and 3-weekly (70 mg/m2) regimen, respectively, and estramustine was administered combining with docetaxel in 77 (48.4%). Following docetaxel-based chemotherapy, PSA declined in 118 patients (74.3%), including 87 (54.6%) achieving a PSA decline≥50%, and the median progression-free survival and overall survival (OS) were 2.9 and 23.2 months, respectively. Of several factors examined, univariate analysis identified performance status (PS), significant clinical pain, bone metastasis, schedule of treatment, treatment cycle, and PSA response as significant predictors of OS, of which only PS, treatment cycle, and PSA response appeared to be independently associated with OS on multivariate analysis. The major grade 3-4 toxicities were myelosuppression, including neutropenia, anemia, and thrombocytopenia in 78 (49.1%), 22 (13.8%), and 14 (8.8%), respectively.

CONCLUSIONS

These findings suggest that docetaxel-based chemotherapy is clinically feasible in Japanese men aged≥75 years with mCRPC considering the cancer control as well as safety associated with this therapy.