Browsing by Author "Toivonen, Kirsti Ilona"

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    A Multi-Method Investigation of Factors Associated with Adherence to/Persistence with Adjuvant Endocrine Therapy in Breast Cancer Survivors to Inform Intervention Development
    (2021-08-31) Toivonen, Kirsti Ilona; Campbell, Tavis; Carlson, Linda; Tomfohr-Madsen, Lianne
    Introduction: Adjuvant endocrine therapy (AET) reduces risk of hormone receptor-positive breast cancer recurrence; however, adherence to AET is sub-optimal and prior attempts to improve this have been unsuccessful. This work aimed to better understand factors associated with AET use to inform the development of a behavioural intervention for AET adherence. Methods: A systematic review examined which potentially modifiable factors were most consistently associated with AET adherence. An observational study recruited 133 women to assess potentially modifiable factors associated with self-reported adherence at baseline and objectively measured adherence over 12 months. Finally, a qualitative study interviewed 47 individuals (women who persisted with, women who discontinued, and healthcare providers who manage AET) about factors supporting AET use. Thematic analysis was used to describe the data. Results: Results of the systematic review indicated that self-efficacy and positive decisional balance were most consistently associated with AET adherence. Results of the observational study indicated that side effect severity, then self-efficacy, and finally medication/healthcare-related barriers explained the most unique variance in self-reported adherence at baseline. Only medication/healthcare-related barriers explained unique variance in objectively measured adherence over 12 months. The qualitative study indicated that women who persisted with AET were prepared for side effects, and had effective management strategies, strong rationale for AET use, supportive HCPs, and available resources. Women who discontinued described feeling overwhelmed by side effects, information needs, drawbacks of AET, experiences with HCPs, and contextual factors as relevant to their discontinuation. HCPs described health system- and patient-related barriers, side effect management, and patient provider-interactions as relevant to supporting AET use. General Conclusion: Considering salient factors associated with AET use across the studies (e.g., self-efficacy, side effects) and potential utility of using theory to guide intervention development, social cognitive theory (SCT) was considered as a theoretical framework from which to conceptualize multiple influences on AET use. SCT could also guide selection of potential intervention components and guide understanding of potential mechanisms of change. Considerations for next steps in a phasic and iterative approach to developing an intervention to improve AET adherence are discussed.