Communicating options for advanced breast cancer support and treatment (COAST): Developing a decision support tool.

Abstract

682 Background: In the United States, >170,000 individuals are living with metastatic breast cancer (mBC). New treatments continue to emerge and vary by mode of delivery, length, side effects, and costs. While providers share information about potential risks and benefits of different treatments, accounting for individual preferences and concerns around these decisions may help inform patient treatment choice. Reflecting evidence-based information about treatment options while accounting for patient goals, values, and preferences; decision aids facilitate shared decision making and enhance patient-provider communication. Decision aids focused specifically on supporting patients through mBC treatment choice are lacking. Together with our patient, provider, and community partner stakeholders, we developed COAST (Communicating Options for Advanced breast cancer Support and Treatment) to address this gap. Methods: The development of COAST was guided by the International Patient Decision Aid Standards. First, we formed a stakeholder advisory group, which included three breast oncologists, a patient advocate, and a community partner. Second, through a literature review and discussions with stakeholders, we developed content specific for adults with mBC. Following protocol development and alpha testing by patients and providers, we finalized both web and paper versions of COAST. Results: Between September 2025 and May 2026, we developed COAST, a novel decision support tool for adults with mBC. Core components of COAST include informational/education content about mBC and its treatments, assessment of patients’ values/preferences to guide shared-decision making, and a list of curated patient resources. Conclusions: In the next phase of this study, we will pilot test COAST among 100 adults with mbC treated at three clinics in New York City. We plan to assess the implementation of COAST and collect data regarding its ability to 1) improve patient-provider communication, 2) enhance patient knowledge, 3) increase decisional self-efficacy, and 4) reduce decisional conflict. We seek to empower patients with mBC to identify, prioritize, and communicate their preferences and values; doing so will support a shared decision-making for mBC treatment selection. Findings from our study will shed light on ways to facilitate shared decision-making among diverse patients living with mBC, and inform the refinement and sustainability of COAST, ultimately optimizing care and outcomes for patients.