International breast density and cancer risk assessment workshop: advances, challenges, and emerging solutions, a summary from the 11th IBDW, Kaua'i 2025.

Breast density is one of the strongest risk factors for breast cancer and a key determinant of mammographic sensitivity, yet fundamental questions remain regarding its measurement, biology, and role in individualized risk management. The International Breast Density Workshop (IBDW) has convened biennially since 2002 to advance this field. The 11th IBDW was held in Līhue, Kaua'i, Hawai'i in June 2025, bringing together 85 unique abstracts from researchers, clinicians, and advocates representing 14 countries. The workshop was organized around five thematic sessions covering: the state of the art in risk assessment and imaging biomarkers; biological and environmental modulators of breast density; innovative technology and methods for imaging-based risk assessment; frontiers in integrating clinical, omic, and imaging biomarkers; and community engagement and health equity in screening strategies. An innovative Breast Cancer Risk Board, modeled on the clinical tumor board format, provided a forum for real-time audience engagement on individualized risk management cases. Across sessions, recurring themes included the rapid maturation of AI-based imaging biomarkers, the critical need for validation in racially and ethnically diverse populations, and the importance of standardized density measures for equitable screening recommendations. The 12th IBDW will be held in Maui, Hawai'i, June 2-4, 2027.