Implementing mobile mammography in primary care: a community-based Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) evaluation.

BACKGROUND: Mobile mammography units (MMU) address disparities in breast cancer screening. Challenges integrating MMU into routine healthcare delivery limit their sustained impact, particularly in underserved communities. PURPOSE: This study evaluated the implementation of a mobile mammography program embedded within primary care practices described within the Practical, Robust Implementation and Sustainability Model (PRISM) and evaluated according to the Reach, Effectiveness, Adoption, Implementation, and Maintenance (RE-AIM) framework. METHODS: We conducted a REAIM implementation evaluation of a MMU program delivered from 2013 to 2019 within six primary care practices serving medically underserved populations. Data sources included administrative records, Patient Ambassador outreach and screening day logs, provider focus groups, and patient satisfaction surveys. RE-AIM domains were used to assess organizational uptake and sustainability, implementation processes, patient reach, and patient-reported experience. RESULTS: Practices adopted MMU integration with varied duration and intensity. Predictable screening schedules and clinic-based appointment prescheduling achieved greater screening completion and sustainability than sites relying primarily on patient outreach. Patient Ambassadors facilitated implementation through scheduling, logistics, and patient education, reducing administrative burden on clinical staff. Key implementation challenges included limited MMU capacity, missed appointments, staffing demands, and MMU accessibility constraints. Reach included over 6400 completed mammograms and more than 10 000 outreach calls. Patient satisfaction and intention to use the MMU again remained high throughout the program. CONCLUSIONS: Embedding MMU within primary care, supported by Patient Ambassadors, can expand access to breast cancer screening in underserved communities. Sustainable implementation requires predictable scheduling, adequate coordination capacity, leadership engagement, and adaptation to local clinical and patient contexts.