title: Effectiveness of Digital Breast Tomosynthesis Compared With Digital Mammography: Outcomes Analysis From 3 Years of Breast Cancer Screening.
abstract: OBJECTIVE
  Breast cancer screening with digital breast tomosynthesis (DBT) combined with digital mammography (DM) decreases false-positive examinations and increases cancer detection compared with screening with DM alone. However, the longitudinal performance of DBT screening is unknown.
  
  
  OBJECTIVE
  To determine whether the improved outcomes observed after initial implementation of DBT screening are sustainable over time at a population level and to evaluate the effect of more than 1 DBT screening at the individual level.
  
  
  METHODS
  Retrospective analysis of screening mammography metrics was performed for all patients presenting for screening mammography in an urban, academic breast center during 4 consecutive years (DM, year 0; DBT, years, 1-3). The study was conducted from September 1, 2010, to September 30, 2014 (excluding September 2011, which was the transition period from DM to DBT), for a total of 44 468 screening events attributable to a total of 23 958 unique women. Differences in screening outcomes between each DBT year and the DM year, as well as between groups of women with only 1, 2, or 3 DBT screenings, were assessed, and the odds of recall adjusted for age, race/ethnicity, breast density, and prior mammograms were estimated. Data analysis was performed between February 16 and October 26, 2015.
  
  
  METHODS
  Digital mammography screening supplemented with DBT.
  
  
  METHODS
  Recall rates, cancer cases per recalled patients, and biopsy and interval cancer rates were determined.
  
  
  RESULTS
  Screening outcome metrics were evaluated for a total of 44 468 examinations attributable to 23 958 unique women (mean [SD] age, 56.8 [11.0] years) over a 4-year period: year 0 cohort (DM0), 10 728 women; year 1 cohort (DBT1), 11 007; year 2 cohort (DBT2), 11 157; and year 3 cohort (DBT3), 11 576. Recall rates rose slightly for years 1 to 3 of DBT (88, 90, and 92 per 1000 screened, respectively) but remained significantly reduced compared with the DM0 rate of 104 per 1000 screened. Reported as odds ratios (95% CIs), the findings were DM vs DBT1, 0.83 (0.76-0.91, P < .001); DM vs DBT2, 0.85 (0.78-0.93, P < .001); and DM vs DBT3, 0.87 (0.80-0.95, P = .003). The cancer cases per recalled patients continued to rise from DM0 rate of 4.4% to 6.2% (P = .06), 6.5% (P = .03), and 6.7% (P = .02) for years 1 to 3 of DBT, respectively. Outcomes assessed for the most recent screening for individual women undergoing only 1, 2, or 3 DBT screenings during the study period demonstrated decreasing recall rates of 130, 78, and 59 per 1000 screened, respectively (P < .001). Interval cancer rates, determined using available follow-up data, decreased from 0.7 per 1000 women screened with the use of DM to 0.5 per 1000 screened with the use of DBT1.
  
  
  CONCLUSIONS
  Digital breast tomosynthesis screening outcomes are sustainable, with significant recall reduction, increasing cancer cases per recalled patients, and a decline in interval cancers.
authors.affiliation: Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
authors.forename: Elizabeth S
authors.initials: ES
authors.lastname: McDonald
authors.affiliation: Computational Breast Imaging Group, University of Pennsylvania, Philadelphia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Oustimov
authors.affiliation: Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
authors.forename: Susan P
authors.initials: SP
authors.lastname: Weinstein
authors.affiliation: Division of General Internal Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
authors.forename: Marie B
authors.initials: MB
authors.lastname: Synnestvedt
authors.affiliation: Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
authors.forename: Mitchell
authors.initials: M
authors.lastname: Schnall
authors.affiliation: Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia.
authors.forename: Emily F
authors.initials: EF
authors.lastname: Conant
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000071060:Breast Density; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000473:pathology; D055088:Early Detection of Cancer; D005260:Female; D006801:Humans; D008327:Mammography; D008403:Mass Screening; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D012307:Risk Factors