Comparison of performance metrics with digital 2D versus tomosynthesis mammography in the diagnostic setting

Objectives To compare performance metrics between digital 2D mammography (DM) and digital breast tomosynthesis (DBT) in the diagnostic setting. Methods Consecutive diagnostic examinations from August 2008 to February 2011 (DM group) and from January 2013 to July 2015 (DM/DBT group) were reviewed. Core biopsy and surgical pathology results within 365 days after the mammogram were collected. Performance metrics, including cancer detection rate (CDR), abnormal interpretation rate (AIR), positive predictive value (PPV) 2, PPV3, sensitivity, and specificity were calculated. Multivariable logistic regression models were fit to compare performance metrics in the DM and DM/DBT groups while adjusting for clinical covariates. Results A total of 22,883 mammograms were performed before DBT integration (DM group), and 22,824 mammograms were performed after complete DBT integration (DM/DBT group). After adjusting for multiple variables, the CDR was similar in both groups (38.2 per 1,000 examinations in the DM/DBT group versus 31.3 per 1,000 examinations in the DM group, p = 0.14); however, a higher proportion of cancers were invasive rather than in situ in the DM/DBT group [83.7% (731/873) versus 72.3% (518/716), p < 0.01]. The AIR was lower in the DM/DBT group ( p < 0.01), and PPV2, PPV3, and specificity were higher in the DM/DBT group (all p = 0.01 or p < 0.01). Conclusions Complete integration of DBT into the diagnostic setting is associated with improved diagnostic performance. Increased utilization of DBT may thus result in better patient outcomes and lead to a shift in the benchmarks that have been established for DM. Key Points • Integration of tomosynthesis into the diagnostic setting is associated with improved performance. • A higher proportion of cancers are invasive rather than in situ with digital breast tomosynthesis. • Increased utilization of tomosynthesis may lead to a shift in established benchmarks.