Interventions to improve endocrine therapy adherence in breast cancer survivors: what is the evidence?

Endocrine therapy reduces the risk of breast cancer recurrences and mortality in hormone receptor-positive (HR+) breast cancer survivors. However, non-adherence to treatment remains a significant problem. The aim of this study was to review current literature and ongoing trials to identify interventions employed to improve adherence to adjuvant endocrine therapy (AET) in breast cancer survivors.

We searched PubMed and the National Library of Medicine registry of clinical trials using the terms "breast cancer" and "adherence" or "compliance" and "intervention" and "medication" or "endocrine therapy" or "hormone therapy" to identify published studies as well as ongoing clinical trials.

Three hundred and sixty-three studies were identified; five studies met the inclusion criteria. Most studies enrolled postmenopausal women diagnosed with early stage HR+ breast cancer. Providing educational materials was the most common intervention implemented to improve adherence to one or more aromatase inhibitors. None of the studies found a significant improvement in adherence with the intervention evaluated. Twelve clinical trials investigating various interventions, mostly based on technology, to improve AET adherence were also identified.

Improving adherence to AET in HR+ breast cancer survivors is an urgent medical need. While newer clinical trials are overcoming some of the limitations seen with published studies, tailored interventions led by clinicians need further investigation.

Our study highlights the unmet clinical need to develop and test feasible interventions to improve AET adherence in HR+ breast cancer survivors to extend their long-term survival.