Breast Cancer Screening Using Tomosynthesis or Mammography: A Meta-analysis of Cancer Detection and Recall

Background: Tomosynthesis approximates a 3D mammogram of the breast, reducing parenchymal overlap that masks cancers or creates false "lesions" on 2D mammography, and potentially enabling more accurate detection of breast cancer. We compared breast cancer screening detection and recall in asymptomatic women for tomosynthesis vs 2D mammography. Methods: A systematic review and random effects meta-analysis were undertaken. Electronic databases (2009-July 2017) were searched for studies comparing tomosynthesis and 2D mammography in asymptomatic women who attended population breast cancer screening and reporting cancer detection rate (CDR) and recall rate. All statistical tests were two-sided. Results: Seventeen studies (1 009 790 participants) were included from 413 citations. The pooled incremental CDR for tomosynthesis was 1.6 cancers per 1000 screens (95% confidence interval CI = 1.1 to 2.0, P < .001, I2 = 36.9%). Incremental CDR was statistically significantly higher for European/Scandinavian studies, all using a "paired" design where women had both tests (2.4 per 1000 screens, 95% CI = 1.9 to 2.9, P < .001, I2 = 0.0%) compared with US ("unpaired") studies (1.1 per 1000 screens, 95% CI = 0.8 to 1.5, P < .001, I2 = 0.0%; P < .001 between strata). The recall rate for tomosynthesis was statistically significantly lower than for 2D mammography (pooled absolute reduction = -2.2%, 95% CI = -3.0 to -1.4, P < .001, I2 = 98.2%). Stratified analyses showed a decrease in US studies (pooled difference in recall rate = -2.9%, 95% CI = -3.5 to -2.4, P < .001, I2 = 92.9%) but not European/Scandinavian studies (0.5% increase in recall, 95% CI = -0.1 to 1.2, P = .12, I2 = 93.5%; P < .001 between strata). Results were similar in sensitivity analyses excluding studies with overlapping cohorts. Conclusions: Tomosynthesis improves CDR and reduces recall; however, effects are dependent on screening setting, with greater improvement in CDR in European/Scandinavian studies (biennial screening) and reduction in recall in US studies with high baseline recall.