Systematic Literature Review of the Impact of Endocrine Monotherapy and in Combination with Targeted Therapy on Quality of Life of Postmenopausal Women with HR+/HER2-Advanced Breast Cancer

Introduction: A major treatment goal for advanced breast cancer (ABC) is to maintain or ideally improve patient quality of life (QoL). Given the changing disease landscape, this systematic literature review (SLR) aims to assess the impact of endocrine therapies (ET), including ET monotherapy (ET mono) and ET combined with targeted therapy (ET + TT), on QoL of women with HR+/HER2- ABC. Methods: A SLR was conducted to identify randomized controlled trials (RCTs) meeting the following criteria: (1) included ET mono or ET + TT, (2) reported QoL outcomes, (3) focused on women with HR+/HER2- ABC, and (4) published after 2007 (when standardized HER2 testing became available). The databases searched included MEDLINE, EMBASE, Cochrane Library, and key conference proceedings from 2013 to 2016. QoL outcomes for ET mono, ET + TT, and comparisons between the two were summarized from the identified trials. Results: A total of 11 studies (representing 6 RCTs) were identified. The study populations included first-line (5 studies) and ET-failure settings (6 studies). Across settings, global health status (GHS) maintained or deteriorated slightly on these treatments during the trial period. Time to deterioration (TTD) in QoL measured by GHS was analyzed in 6 studies and 4 RCTs. In the first-line setting, reported median TTD in GHS was similar between ET mono and ET + TT (7.2-13.8 months in ET mono; 11.1 months in ET + TT). In the ET-failure setting, ET + TT showed significantly longer TTD vs. ET mono in GHS (median 5.6-8.4 months in ET mono and 8.3-11.7 months in ET + TT) and some additional domains. Conclusions: ET + TT users experienced similar QoL in the first-line and ET-failure setting relative to patients on ET mono. Moreover, ET +4 TT users experienced better QoL outcomes in some domains in the ET-failure setting relative to ET mono users.