Enhancing the OncoSim-Breast model using Canadian breast density information

Breast cancer is the most commonly diagnosed cancer among women in Canada. Breast density substantially influences breast cancer risk and mammography performance. However, OncoSim-Breast, a Canadian microsimulation model representing breast cancer control, including cancer onset, screening, and survival, has not previously explicitly accounted for breast density. This study describes the incorporation of density-specific parameters—prevalence, relative risk of breast cancer, and digital mammography performance (sensitivity and specificity)—using data from five Canadian provinces, into the OncoSim-Breast model. Calibration experiments and internal validations were conducted to ensure the updated OncoSim-Breast model aligned with observed data from the Canadian Cancer Registry.