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

Abstract

82 Background: Most men who die of prostate cancer are older than 70 years, and the impact of therapy in this population is poorly defined. 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. Methods: The results of CHAARTED showed an overall survival (OS) benefit for the addition of docetaxel to ADT in men with mHSPC. In a secondary 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. Additionally, we compared adverse events, therapy completion rate, and subsequent treatment patterns between these two groups using Chi-squared tests. Results: Of the 790 patients enrolled, 177 (22.4%) were ≥70 years. A greater proportion of older men had an impaired performance status (Eastern Cooperative Oncology Group 1-2: 36.7% vs. 28.6%, p=0.038) and prior local therapy (31.7% vs. 25.9%, p<0.001) compared to younger men. 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 all 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% of older men vs. 26.8% of younger men, p=0.69). The rate of any Grade 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: In summary, older men with mHSPC who were eligible to participate in a clinical trial had similar OS benefit and clinical outcomes compared to younger men when receiving docetaxel chemotherapy + ADT. Oncologists should consider docetaxel chemotherapy as a favorable treatment option for older men with mHSPC who are fit for chemotherapy. Clinical trial information: NCT00309985.