Diagnostic performance of digital breast tomosynthesis (DBT) versus digital mammography (DM) in a population clinically referred for breast imaging – a retrospective cohort study

PURPOSE: To compare the performance of Digital Breast Tomosynthesis (DBT) with Digital Mammography (DM) in patients clinically referred for breast imaging. METHODS: Diagnostic performance of DBT (in 2016, after transition to DBT) was compared with DM (in 2011, before the transition) in consecutively referred patients (N = 10,742 exams). Reference standard was outcomes from all tests including histopathology and clinical review within the same year. Primary outcome was area under receiver operating characteristic curve (AUC-ROC). RESULTS: Cancer rates did not differ between DBT (1.72 % (CI 1.38-2.15 %)) and DM (1.71 % (CI 1.40-2.08 %)). AUC-ROC was similar for DBT (0.91 (CI 0.87-0.95)) and DM (CI 0.91 (0.88-0.95)). Abnormal interpretation rate for DBT was 2.83 % (CI 2.38-3.36 %) and for DM it was 2.17 % (CI 1.82-2.58 %), and the biopsy rate for DBT was 8.2 % (CI 7.4-9.0 %) and for DM it was 9.9 % (CI 9.1-10.6 %)). In patients with dense breasts (vs overall cohort) AUC-ROC and sensitivity were lower for both DM and DBT. Within this subgroup, AUC-ROC for DBT was 0.90 (CI 0.84-0.95) and for DM it was 0.85 (CI 0.79-0.92), sensitivity was 78.2 % (CI 65.0-88.2 %) for DBT and 64.8 % (CI 50.6-77.3 %) for DM, and ultrasound was accurate whether it was used with DBT (AUC-ROC 0.95 (CI 0.91 - 0.99)) or DM (AUC-ROC 0.95 (CI 0.90 - 0.99)) CONCLUSION: In clinically referred patients, diagnostic accuracy and diagnostic yield were similar between DBT and DM. DBT may have a higher abnormal interpretation rate but a lower biopsy rate. DBT may be more accurate than DM in dense breasts.