Digital Breast Tomosynthesis (DBT) to Characterize MRI-Detected Additional Lesions Unidentified at Targeted Ultrasound in Newly Diagnosed Breast Cancer Patients

Objectives: Preoperative breast magnetic resonance (MR) often generates additional suspicious findings needing further investigations. Targeted breast ultrasound (US) is the standard tool to characterize MR additional lesions. The purpose of this study is to evaluate the potential role of digital breast tomosynthesis (DBT) to characterize MR detected additional findings, unidentified at targeted breast US. Methods: This prospective study included women who a) had biopsy-proven, newly diagnosed breast cancers detected at conventional 2D mammography and/or US, referred to breast MR for tumour staging; and b) had DBT if additional MR findings were not detected at targeted (‘second look’) US. Results: In 520 patients, MR identified 164 (in 114 women, 22 %) additional enhancing lesions. Targeted US identified 114/164 (69.5 %) of these, whereas 50/164 (30.5 %) remained unidentified. DBT identified 32/50 of these cases, increasing the overall characterization of MR detected additional findings to 89.0 % (146/164). Using DBT the identified lesions were significantly more likely to be malignant than benign MR-detected additional lesions (p = 0.04). Conclusions: DBT improves the characterization of additional MR findings not identified at targeted breast US in preoperative breast cancer staging. Key points: • Targeted US identified 114 of 164 (69.5 %) additional enhancing lesions at preoperative breast MRI. • DBT identified a further 32 of the 50 lesions unidentified on targeted US. • DBT improved the characterization of additional MR findings for breast cancer staging.