Diagnostic management pathways for workup of abnormal screening with digital mammography versus digital breast tomosynthesis.

Purpose: To assess the transition from digital mammography (DM) to digital breast tomosynthesis (DBT) screening, we compared diagnostic work-up type and frequency, work-up pathways, and time to resolution of abnormal screening DBT versus DM.

Methods: This cohort study includes screening exams with an abnormal result from 2011-2020 at 107 facilities across six Breast Cancer Surveillance Consortium registries. Diagnostic work-up included diagnostic DM, diagnostic DBT, ultrasound, magnetic resonance imaging, and biopsy within 90 days of the abnormal screening mammogram. We compared work-up modalities and number of work-up procedures using differences in proportion and 95% confidence intervals (95%CI). Time to diagnostic resolution between DBT and DM was compared with a log-rank test.

Results: Among 77,123 abnormal DBT and 197,589 abnormal DM screening examinations, the number of imaging modalities in the diagnostic pathway was similar. The first work-up procedure was more often ultrasound following abnormal DBT compared to abnormal DM (21.1% vs. 4.7%). Biopsy rates were higher for DBT versus DM (16.2% vs. 14.0%, difference in proportions=2.27 95%CI:1.97-2.58) with biopsies following DM versus DBT more likely surgical versus FNA/core (5.8% vs.3.2%, difference in proportions=2.6, 95%CI:2.19-3.01), resulting in a rate of excision biopsy per 1000 abnormal screens of 5.1 for DBT and 8.0 for DM. Time to diagnostic resolution was similar (median=10 days).

Conclusions: We found differences in the type of diagnostic work-up pathways following an abnormal screening DBT versus DM. While the biopsy rate was higher after abnormal DBT, the biopsy type may be more invasive (surgical excision) after abnormal DM screening.