Benefits of digital breast tomosynthesis: A lesion-level analysis

To compare outcome metrics of digital breast tomosynthesis (DBT) breast cancer screening with full-field digital mammogram (FFDM); specifically, to compare recall rates by the type of recalled finding, and to assess if screening with DBT versus FFDM changes biopsy recommendations and if the likelihood of malignancy varied by lesion type, if detected on DBT or FFDM screening mammogram.

The outcomes of 22,055 FFDM and DBT screening mammograms were retrospectively reviewed. The exams were performed at an academic institution between August 2015 and September 2016. Performance of screening with FFDM versus DBT was compared in terms of recall rate and percentage of recalled lesions resulting in a cancer diagnosis, with subset analyses performed for specific mammographic findings.

The recall rate was 10.6% for FFDM and 8.0% for DBT (p < 0.001). Architectural distortion was more likely to be recalled on DBT screening than FFDM (p = 0.002), and was associated with an increased likelihood of malignancy (p = 0.008). Asymmetries were less likely to be recalled on DBT than FFDM (p < 0.001) screening mammogram, but more likely to be recommended for biopsy when detected on DBT. Calcifications more frequently required short-term follow-up or biopsy on both DBT and FFDM.

DBT screening confers an advantage in detection of architectural distortion representing malignancy. Recall rate of asymmetries are reduced with screening DBT, probably due to reduction of tissue superimposition. Calcifications pose a particularly difficult diagnostic challenge for breast imagers, regardless of screening mammogram type.