Five Consecutive Years of Screening with Digital Breast Tomosynthesis: Outcomes by Screening Year and Round

Background: Limited data exist beyond prevalence rounds of digital breast tomosynthesis (DBT) screening. Purpose: To compare DBT outcomes over multiple years and rounds to outcomes of digital mammography (DM) screening. Materials and Methods: Retrospective analysis included 1 year of DM and 5 years of DBT screening (September 2011 to September 2016); 67 350 examinations were performed in 29 310 women. Recall rate (RR) percentage, cancer detection rate (CDR) per 1000 women screened, false-negative rate per 1000 women screened, positive predictive value of recall (PPV1) percentage, positive predictive value of biopsies performed percentage, sensitivity, and specificity were calculated. Cancers diagnosed within 1 year of screening were captured by means of linkage to state cancer registry, and biologic characteristics were grouped by prognostic factors. Performance trends across DBT rounds were compared with those from DM rounds by using logistic regression to account for examinations in the same woman. Analyses were adjusted for age, race, breast density, baseline examination, and reader. Results: There were 56 839 DBT and 10 511 DM examinations. The mean patient age (+/- standard deviation) was 56 years +/- 11 for the entire cohort, 55 years +/- 11 for the DBT group, and 57 years +/- 11 for the DM group. RRs were significantly lower for the DBT group (8.0%, 4522 of 56 839; 95% confidence interval [CI]: 7.7, 8.2) than for the DM group (10.4%, 1094 of 10 511; 95% CI: 9.8, 11.0) (P < .001). CDRs were higher with DBT (6.0 per 1000 women screened; 95% CI: 5.4, 6.7 per 1000 women screened; 340 of 56 839) than with DM (5.1 per 1000 women screened; 95% CI: 3.9, 6.6 per 1000 women screened; 54 of 10 511) (P = .25), but this difference was not statistically significant. Both RR and CDR remained improved compared with DM for 5 years of DBT at the population level. False-negative rates were slightly lower for DBT (0.6 per 1000 women screened; 95% CI: 0.4, 0.8 per 1000 women screened; 33 of 56 839) than DM (0.9 per 1000 women screened; 0.4, 1.6 per 1000 women screened; nine of 10 511) overall (P = .30), but the difference was not statistically significant. In adjusted analyses, RR, biopsy recommendation rates, and PPV1 were improved for DBT versus DM (P <= .001). Compared with DM, a higher proportion of DBT-detected cancers were invasive (70% [238 of 340] vs 68.5% [37 of 54]) and had poor prognoses characteristics (32.6% [76 of 233] vs 25.0% [nine of 36]). Conclusion: Favorable outcomes with digital breast tomosynthesis screening were sustained over multiple years and rounds. Digital breast tomosynthesis screening was associated with detection of a higher proportion of poor-prognosis cancers than was digital mammography. (C) RSNA, 2020