Subgroups varying in risk and density highlight the potential for stratified breast cancer screening.

Most breast cancer screening programs rely only on demographic data without considering individual risk factors of the population, which might limit their effectiveness by over- and underscreening specific subgroups. Therefore, the aim of this study is to highlight health and economic disparities in outcomes from such a uniform screening strategy. With the microsimulation model MISCAN, we simulated outcomes of the Dutch screening program considering 16 subgroups varying by their 5-year breast cancer risk and breast density. All outcomes showed significant disparities across risk-density subgroups. Notably, women with extremely dense breasts showed a mortality reduction from the current screening of 16-17 % compared to 25-29 % in other groups. Absolute benefits (breast cancer deaths averted, and life-years gained) increased with risk and varied independently by density. The range of false-positive rates varied almost twofold across the span of subgroups and nearly a ninefold difference in the medical costs incurred with lifelong follow-up. These findings emphasize the potential for stratified screening strategies to improve equity in health outcomes and reduce the burden of breast cancer.