Quality of life in men with metastatic castration-resistant prostate cancer treated with enzalutamide or abiraterone: a systematic review and meta-analysis

Background Enzalutamide and abiraterone acetate plus prednisone (AAP) have similar efficacy in metastatic castration-resistant prostate cancer (mCRPC), but different mechanisms of action. The aim was to compare patient-reported health-related quality of life (HRQoL) in men treated with enzalutamide vs AAP for mCRPC. Methods We systematically reviewed the literature in June 2020 according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. Patient-reported outcomes (PROs) until the last follow-up were summarised in a narrative synthesis. Short-term changes (12 weeks) in HRQoL, measured by the Functional Assessment of Cancer Therapy-Prostate total score (FACT-P), were compared between treatment groups and were analysed for enzalutamide and AAP in separate meta-analyses. Higher FACT-P scores indicate better HRQoL. Results Eight studies were included in the systematic review, four of which were randomised clinical trials (RCTs) eligible for the meta-analyses. The meta-analyses showed mean within-subject FACT-P changes from baseline to week 12 of -1.3 points (95% confidence interval [CI] -2.7; 0.1) for enzalutamide and 4.7 points (95% CI -0.1; 9.6) for AAP. One RCT and three non-randomised studies directly compared enzalutamide with AAP. The RCT showed better short-term HRQoL for AAP (6.8 FACT-P-points, 95% CI 1.7; 11.8) and better long-term HRQoL for AAP in men >= 75 years (7.35 FACT-P-points, 95% CI 2.59; 12.11). The non-randomised studies showed no difference in long-term HRQoL but had all a serious risk of bias. Limitations of the included studies include that the PRO in the included trials were inconsistently reported and that only one study defined the HRQoL measures in their published protocol. Conclusions AAP seems to be associated with better short-term HRQoL than enzalutamide. This difference was not apparent at longer follow-up, but the long-term studies had serious risks of bias.