Population-based impact on overall survival after the introduction of docetaxel as standard therapy for metastatic castration resistant prostate cancer

Introduction: Utilization of docetaxel in patients with metastatic castration resistant prostate cancer (mCRPC) remains low despite its demonstrated survival benefit. In a population-based cohort, we sought to determine whether the introduction of docetaxel has improved overall survival (OS). Methods: A retrospective review was conducted of mCRPC patients treated with palliative radiotherapy to bone in British Columbia, Canada. Patients in the pre-docetaxel era (pre-DOC, prior to general availability of docetaxel for CRPC) received radiotherapy to bone (RT-B) from 1998 to 2001 and those in the docetaxel era (DOC) received radiotherapy from 2006 to 2009. Time of first radiotherapy to bone was used to select patients at a similar point in their disease state (i.e., onset of bone pain). The primary objective was to determine median OS in the two eras. Results: Of the 919 patients in the pre-DOC era and the 957 in the DOC era, 7% and 37% received docetaxel, respectively. The median OS from time of first palliative RT was 7.5 months versus 10.3 months (hazard ratio [HR]: 0.79, 95% confidence interval [CI] 0.72-0.87; p < 0.0001) in the pre-DOC and DOC cohorts, respectively. On multivariable analyses, both eras treated (HR 0.84; p = 0.001) and the receipt of docetaxel (HR 0.78; p < 0.001) were significantly associated with OS. Conclusion: Although docetaxel penetrance was <50%, median OS was significantly improved in the DOC era compared to the pre-DOC era. This is the first study to demonstrate that docetaxel improves OS in mCRPC patients at a population level.