Supporting adjuvant endocrine therapy adherence in women with breast cancer: the development of a complex behavioural intervention using Intervention Mapping guided by the Multiphase Optimisation Strategy

Abstract

Background Adjuvant endocrine therapy (AET) reduces the risk of breast cancer recurrence and mortality. However, up to three-quarters of women with breast cancer do not take AET as prescribed. Existing interventions to support adherence to AET have largely been unsuccessful, and have not focused on the most salient barriers to adherence. This paper describes the process of developing four theory-based intervention components to support adherence to AET. Our aim is to provide an exemplar of intervention development using Intervention Mapping (IM) with guidance from the Multiphase Optimisation Strategy (MOST). Methods Iterative development followed the six-stage IM framework with stakeholder involvement. Stage 1 involved a literature review of barriers to adherence and existing interventions, which informed the intervention objectives outlined in Stage 2. Stage 3 identified relevant theoretical considerations and practical strategies for supporting adherence. Stage 4 used information from Stages 1-3 to develop the intervention components. Stages 5 and 6 detailed implementation considerations and evaluation plans for the intervention package, respectively. Results The final intervention package comprised four individual intervention components: Short Message Service to encourage habitual behaviours surrounding medication taking; an information leaflet to target unhelpful beliefs about AET; remotely delivered Acceptance and Commitment Therapy-based guided self-help to reduce psychological distress; and a website to support self-management of AET side-effects. Considerations for implementation within the NHS, including cost, timing and mode of delivery were outlined, with explanation as to how using MOST can aid this. We detail our plans for the final stage of IM which involve feasibility testing. This involved planning an external exploratory pilot trial using a 24−1 fractional factorial design, and a process evaluation to assess acceptability and fidelity of intervention components and overall trial experience. Conclusions We have described a systematic and logical approach for developing a theoretically informed intervention package to support medication adherence in women with breast cancer using AET. Further research to optimise the intervention package, guided by MOST, has the potential to lead to more effective, efficient and scalable interventions.

Factors influencing the first and the fifth years adherence to adjuvant endocrine therapy in breast cancer patients in a low income country

“…We analyzed the potential influence the type of AET medication could have on the quality of life score domain regarding symptoms in both cohorts separately (table 8): we detected no difference between tamoxifen and aromatase inhibitors in the worsening of quality of life in any of the cohorts (p=0.318 for the A cohort and p=0.521 for the B cohort). In fact, many publications have been released guiding health professionals about the importance of managing the adverse effects of AET, with the aim of optimizing adherence rates and improving the quality of life of patients [26,27,28] To date, there is no gold standard method for adherence evaluation. In spite of the data published by Pistilli et al in 2020 [11], in which self-declared nonadherence to AET and serum assessment of tamoxifen below a threshold were significantly associated, biochemical evaluation of AET medications or its metabolites is not validated for clinical practice.…”

Refining and optimising a behavioural intervention to support endocrine therapy adherence (ROSETA) in UK women with breast cancer: protocol for a pilot fractional factorial trial

“…An overview of behavioural support programmes for women using AET reported at least 15 ongoing trials targeting AET adherence 17. Among adequately powered trials of AET interventions, there are few positive findings 18–20.…”

“…Among adequately powered trials of AET interventions, there are few positive findings 18–20. This may be explained by the reliance on interventions involving the provision of written information; which may address some adherence barriers, but is unlikely to address the complex issues underpinning most medication taking behaviours 17 21. As with many long-term conditions where treatment non-adherence is a problem, intervention programmes may require multiple active components to target a range of key determinants.…”

“…As part of the preparatory phase of MOST, we used Intervention Mapping to develop a theoretically informed intervention package 17 26. We identified several modifiable factors associated with AET adherence,27–30 selecting four of the strongest determinants as intervention targets 17. Four intervention components were developed or adapted to address these targets.…”