Dense Breast Ultrasound Screening After Digital Mammography Versus After Digital Breast Tomosynthesis

OBJECTIVE. The objective of this study was to compare the yield of dense breast ultrasound (US) screening after digital mammography (DM) versus after digital breast tomosyn-thesis (DBT). MATERIALS AND METHODS. For this institutional review board-approved, HIPAA-compliant study, we retrospectively searched databases at two tertiary breast imaging centers and an office practice staffed by the same fellowship-trained breast radiologists for screening US examinations from October 1, 2014, to September 30, 2016. Prior DM versus DBT and screening US and pathology results were recorded. Mammographically occult cancers detected with US and additional benign lesions requiring biopsy were calculated. Differences between DM and DBT were compared using the two-sample proportions z test. RESULTS. A total of 3183 screening breast US examinations were performed, 1434 (45.1%) after DM and 1668 (52.4%) after DBT. Of the 3183 examinations, 81 (2.5%) had no prior mammogram available. Of the 122 DM and DBT patients for whom biopsy or cyst aspiration was recommended (all BI-RADS assessment category 4 or BI-RADS assessment category 5 studies), 118 (96.7%) had biopsy or cyst aspiration results available. Of the 36 biopsies or aspirations after DM, 6 (16.7%) were malignant and 30 (83.3%) were benign; of the 82 biopsies or aspirations after DBT, 11 (13.4%) were malignant and 71 (86.6%) were benign (p = 0.8583). The additional cancer detection rate by US after DM was 5/1434 or 3.5 per 1000 women screened and after DBT was 5/1668 or 3.0 per 1000 women screened (p = 0.9999). CONCLUSION. No significant difference in additional cancer detection rate was found with screening US after DM versus after DBT.