Background: The successful use of hormone therapy (HT) has contributed to improved 5-year cause-specific breast cancer survival rates, and evidence shows that long-term use produces a larger reduction in recurrence and mortality, with nearly 50% reduction in breast cancer mortality during the second decade after diagnosis. Despite the proven benefits, hormone therapy adherence is suboptimal (less than 80% of daily doses taken), and about 33% of women who are prescribed HT do not take their medication as prescribed and are at increased risk of disease recurrence and increased mortality. Smartphone ownership has increased substantially over the past decade, providing an extraordinary opportunity for innovation in the delivery of tailored interventions to improve patients' adherence to hormonal therapy. Purpose: We present preliminary results of a pilot study that involves a theory-based, culturally tailored, interactive mobile app + patient navigation to improve adherence to HT among breast cancer patients attending the breast clinic at the Mays Cancer Center (MCC). Methods: This is a 2-group parallel, randomized control trial that is currently recruiting 120 breast cancer patients and randomly assigning them to the intervention (60) or the control (60) group. The intervention group receives two components: 1) the HT Helper phone app; and 2) assistance from a patient navigator who will provide educational, psychosocial support and reinforcement, address common barriers, and facilitate the interaction with the medical team as needed. The control group receives the usual care and information provided by the MCC's breast clinic to patients undergoing HT. The app and navigation support are based in Social Cognitive Theory and principles of motivational interviewing. Results: Due to the COVID-19 pandemic, we were forced to suspend the start of the intervention until May 2021. We have recruited 27 patients and will present a general description of participants and preliminary results of the 3-month follow-up. This theory-based intervention will empower patients' self-monitoring and management. It will facilitate patient education, identification/reporting of side effects, delivery of self-care advice, and simplify communication between the patient and the oncology team. Conclusions: The anticipated outcome is a scalable, evidence-based, and easily disseminated intervention with potentially broad use to patients using HT and other oral anticancer agents. The ultimate goal of this innovative multi-communication intervention is to improve overall survival and life expectancy, enhance quality of life, reduce recurrence, and decrease healthcare costs.

Citation Format: Patricia Chalela, Edgar Muñoz, Vivian Cortez, Armida Flores, Pramod Sukumaran, Cliff Despres, Devasena Inupakutika, David Akopian, Amelie G. Ramirez. Improving adherence to hormone therapy among breast cancer patients through a mobile app and patient navigation: Preliminary results [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-082.