Impact of Breast Density on Screening Performance Metrics: An Analysis of 301,400 Screening Digital Breast Tomosynthesis (DBT) Examinations.

[RATIONALE AND OBJECTIVES] As of September 2024, the FDA requires that breast imaging practices inform women about their breast density. This study aimed to evaluate the impact of breast density on the performance metrics of screening digital breast tomosynthesis (DBT) examinations.

[MATERIALS AND METHODS] We retrospectively reviewed screening DBT examinations performed from 2013 to 2019 at a single academic medical center. Performance metrics were calculated according to the 5th Edition of the BI-RADS Atlas. Associations between breast density and screening performance were examined using multivariable logistic regression with generalized estimating equations.

[RESULTS] The cohort included 111,143 women (mean age, 59 ± 11 years) with 301,400 DBT examinations. Breast density was almost entirely fatty (category A) in 8.8%, scattered areas of fibroglandular density (B) in 50.5%, heterogeneously dense (C) in 36.9%, and extremely dense (D) in 3.8%. Cancer detection rates (CDR, per 1000 exams) were 3.4, 5.6, 5.2, and 3.7 for categories A-D, respectively. Sensitivities were 92.8%, 90.1%, 81.0%, and 61.8%. Specificities were 96.7%, 94.4%, 92.5%, and 93.3%. Category D was associated with significantly lower sensitivity than each of the other categories (adjusted odds ratios [aOR] 0.19-0.43, p<0.01 for all). It was associated with significantly lower specificity than almost entirely fatty tissue (aOR 0.64, p<0.001) but not the other two density categories.

[CONCLUSION] Dense breast tissue significantly decreases the sensitivity of screening DBT. These findings highlight the need to report and consider breast density in screening recommendations and necessitate further research on more effective screening regimens for women with dense breast tissue.