Additional ultrasound in women with dense breasts in a breast cancer-screening program based on digital breast tomosynthesis: evidences on cancer detection, false positives and associated costs.

Breast density is associated with increased risk of breast cancer (BC) and reduces mammography performance. Supplemental ultrasound (US) improves the performance of mammography screening programs in women with dense breasts but only few evidences are available about its added value when digital breast tomosynthesis (DBT) screening is performed. Our study evaluated the contribution of US in detecting BC in women with dense breasts in a screening program based on DBT. From February 2022 to October 2023, asymptomatic women (age range, 50-69 years) attending BC Screening in Verona, Italy, were prospectively recruited. Women underwent DBT and automatic breast density evaluation. Participants with negative DBT and dense breasts were invited to additional breast US. 785/12351 (6.3%) consecutive eligible women had dense breasts. BC was suspected on the basis of DBT in 106/785 (13.5%) women and 5 cancers were diagnosed [cancer detection rate (CDR) for DBT = 6.37 per 1000 screens]. 584/679 (86.0%) DBT-negative patients agreed to US and the incremental CDR of US was 1.7 per 1000 women (1/584). US caused additional investigations in 6/584 (1.03%) women (6 core biopsies) with a benign result in 5/584 (0.86%). The cost per each additional cancer detected by US only was € 25,961,95. In conclusion, in a DBT-based screening setting, the benefit of adding US for women with dense breasts is limited and entails substantial costs.