A systematic review of interventions to improve adherence to endocrine therapy

Purpose Adherence to endocrine therapy for hormone positive breast cancer is a significant problem, especially in minority populations. Further, endocrine therapy reduces recurrence and thus mortality. However, little data are available on interventions to improve adherence. The authors conducted a systematic review to examine the impact of interventions, strategies, or approaches aimed to improve endocrine therapy adherence among women with breast cancer. A secondary aim was to determine if interventions had any cultural modifications. Methods Two of the authors examined articles published between 2006 and 2017 from a wide variety of databases using Covidence systematic review platform. Results In total, 16 eligible studies met criteria for review including 4 randomized controlled trials, 4 retrospective studies, and 8 with various observational designs. Eligible studies used a broad range of definitions for adherence and measured adherence by self-report, medical records, claims data, and combinations of these. All used 80% medication possession ratio as a standard for adherence. Patient information/education was the most frequent intervention strategy but did not demonstrate a significant effect except in one study. Significant results were noted when education was combined with communication strategies. Conclusions Researchers need a standard definition for adherence and a reliable measure that is feasible to use in a variety of studies. While education may be a necessary component of an intervention, when used alone, it is not a sufficient approach to change behavior.