Baseline Screening Mammography: Performance of Full-Field Digital Mammography Versus Digital Breast Tomosynthesis

Baseline mammography studies have significantly higher recall rates than mammography studies with available comparison examinations. Digital breast tomosynthesis reduces recalls when compared with digital mammographic screening alone, but many sites operate in a hybrid environment. To maximize the effect of screening digital breast tomosynthesis with limited resources, choosing which patient populations will benefit most is critical. This study evaluates digital breast tomosynthesis in the baseline screening population.

Outcomes were compared for 10,728 women who underwent digital mammography screening, including 1204 (11.2%) baseline studies, and 15,571 women who underwent digital breast tomosynthesis screening, including 1859 (11.9%) baseline studies. Recall rates, cancer detection rates, and positive predictive values were calculated. Logistic regression estimated the odds ratios of recall for digital mammography versus digital breast tomosynthesis for patients undergoing baseline screening and previously screened patients, adjusted for age, race, and breast density.

In the baseline subgroup, recall rates for digital mammography and digital breast tomosynthesis screening were 20.5% and 16.0%, respectively (p = 0.002); digital breast tomosynthesis screening in the baseline subgroup resulted in a 22% reduction in recall compared with digital mammography, or 45 fewer patients recalled per 1000 patients screened. Digital breast tomosynthesis screening in the previously screened patients resulted in recall reduction of 14.3% (p < 0.001; p for interaction = 0.21). The recall rate reduction for baseline screening was especially pronounced in women younger than 50 years (p = 0.005). DBT implementation resulted in an increase in cancer detection in the baseline subgroup of 40.5% versus an increase in the previously screened subgroup of 17.4%. DBT implementation resulted in an increase in PPV1 in the baseline subgroup of 85% versus 35.3% in the previously screened subgroup, although the p-interaction was not significant.

If resources are limited, women younger than 50 years who are undergoing baseline screening or do not have prior available mammograms may benefit more from digital breast tomosynthesis than from digital mammography alone.