Effect of integrating digital breast tomosynthesis (3D-mammography) with acquired or synthetic 2D-mammography on radiologists' true-positive and false-positive detection in a population screening trial: A descriptive study

Background: We previously reported the Screening with tomosynthesis or standard mammography-2 (STORM-2) trial, showing that tomosynthesis (3D-mammography) screening detected more cancers than 2D-mammography in double-reading practice. In this study, we report reader-specific detection measures for radiologists who performed the screen-reading in this trial. Methods: This is a sub-study of the STORM-2 trial which prospectively integrated 3D-mammography with acquired or synthetized 2D-mammograms in parallel double-reading arms. Asymptomatic women ≥49 years who attended population-based screening (Trento, 2013-2015) were recruited. Screening participants were recalled at any positive sequential screen-read in either reading arm of the trial. Radiologist-specific detection measures were calculated for each of seven radiologists who performed screen-reads: number of detected cancers, proportion of true-positive (TP) detection, and number and rate of false-positive (FP) recalls (FPR). We estimated incremental cancer detection rate (CDR) from integrating 3D-mammography in screen-reading. Results: Across all radiologists, TP detection (relative sensitivity) ranged between: 46% and 100% (median 59.5%) for 2D-mammography; 75% and 100% (median 76%) for integrated 2D/3D-mammography screening; 56% and 76% (median 64%) for 2Dsynthetic; 67% and 88% (median 78%) for 2Dsynthetic/3D-mammography. Integrating 3D-mammography led to incremental CDRs between 0/1000 and 3.5/1000 screens. FPR ranged between: 1.2% and 2.7% (median 2.25%) for 2D-mammography; 1.5% and 3.4% (median 2.75%) for 2D/3D-mammography; 1.6% and 4.6% (median 2.4%) for 2Dsynthetic; and 1.8% and 6.7% (median 3.0%) for 2Dsynthetic/3D-mammography. Conclusions: There was variability in the magnitude of effect from integrating 3D-mammography (relative to screen-reading with acquired or synthesised 2D-mammography alone) on individual radiologist's TP and FP detection, although there was an overall pattern of increasing cancer detection and also increasing FP recall for most readers.