Outcomes of older men receiving docetaxel for metastatic hormone-sensitive prostate cancer

Background Most men who die of prostate cancer are older than 70 years. The ChemoHormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer (CHAARTED) randomized men of all ages with metastatic hormone-sensitive prostate cancer (mHSPC) to receive androgen deprivation therapy (ADT) with or without docetaxel demonstrating an overall survival (OS) benefit for docetaxel. Methods In a post-hoc analysis of this trial, we assessed patient characteristics and OS in patients >= 70 years ("older men") versus <70 years ("younger men") with Cox proportional hazards models. In addition, we compared adverse events, therapy completion rate, and subsequent treatment patterns between these two groups using Chi-squared tests. Results 177 (22.4%) patients were >= 70 years. Docetaxel + ADT resulted in improved OS in both older and younger men (Hazard Ratio [HR] 0.45, 95%CI: 0.25-0.80 for older men; HR 0.71, 95%CI: 0.53-0.95 for younger men). This treatment benefit was seen for subgroups of older men with high volume disease (HR 0.43, 95%CI 0.23-0.79) and de novo metastatic disease (HR 0.36, 95%CI 0.19-0.69). A similar proportion of older and younger men completed six cycles of docetaxel (82.6% vs. 87.1%, p = 0.28). Rates of grade 3-5 adverse events were similar between older and younger men (36.8% vs. 26.8%, respectively, p = 0.069). The rate of any Grades 4-5 adverse events did not differ significantly between older and younger men (14.9% vs. 11.9%, respectively, p = 0.46). In the control arm, a smaller proportion of older men received subsequent cancer treatments (34.4% vs. 51.5%, p = 0.017) or subsequent docetaxel (25.6% vs. 37.6%, p = 0.035) compared to younger men. Conclusions Older men with mHSPC had similar OS benefit and clinical outcomes compared to younger men when receiving docetaxel + ADT. Oncologists should consider docetaxel chemotherapy as a favorable treatment option for older men with mHSPC who are fit for chemotherapy.