Tomosynthesis vs Digital Mammography Screening in Women with a Family History of Breast Cancer

Importance Evidence on screening outcomes with digital breast tomosynthesis (DBT) vs digital mammography (DM) in women with a family history of breast cancer is limited. Objective To compare the performance of DBT and DM screening in women with a family history of breast cancer overall and subdivided by breast cancer family history category, breast density, age group, screening interval, and screening round, and to describe characteristics of cancers detected on screening vs interval cancers. Design, Setting, and Participants In this comparative cohort study at imaging facilities affiliated with the Breast Cancer Surveillance Consortium, adult women 18 years and older with a self-reported family history of breast cancer who underwent DBT or DM from 2011 to 2018 were included, with a 1-year follow-up for breast carcinoma. Data analysis was performed between November 2023 and August 2024. Exposures DBT or DM. Main Outcomes and Measures The main outcomes were absolute risk difference (ARD) between DBT and DM for recall rate, cancer detection rate, interval cancer rate, advanced cancer rate, biopsy rate, positive predictive values, sensitivity, and specificity, with inverse probability of treatment weighting. Results A total of 208 945 women with a family history of breast cancer undergoing 502 357 screening examinations were included in the sample. Median (IQR) age was 58 (50-66) and 57 (49-66) years for the DBT and DM groups, respectively. Adjusted ARDs (DBT vs DM) were significant for recall rate (−1.51%; 95% CI, −2.42% to −0.59%) and specificity (1.56%; 95% CI, 0.65%-2.46%) in the overall cohort of 121 698 DBT and 380 561 DM examinations and among women with 1 first-degree relative (recall rate ARD, −1.72%; 95% CI, −2.70% to −0.74%; specificity ARD, 1.75%; 95% CI, 0.81%-2.69%). Among those with only second-degree relatives, the biopsy rate for DBT was significantly higher (ARD, 0.39%; 95% CI, 0.18%-0.61%). Significant ARDs were observed for the ductal carcinoma in situ detection rate (−0.71 per 1000 examinations; 95% CI, −1.03 to −0.38 per 1000 examinations) in women with almost entirely fatty breasts; recall rate (−1.90%; 95% CI, −2.88% to −0.92%) and specificity (1.93%; 95% CI, 0.97%-2.89%) in women with scattered fibroglandular densities. Significant ARDs were also observed for the positive predictive value for recall (1.75%; 95% CI, 0.84%-2.67%) in heterogeneously dense breasts, as well as the biopsy rate (0.48%; 95% CI, 0.16%-0.80%) and advanced cancer rate (−0.61 per 1000 examinations; 95% CI, −1.02 to −0.20 per 1000 examinations) in extremely dense breasts. DBT screening had a higher proportion than DM of screen-detected early-stage, invasive cancers with favorable prognostic characteristics. Conclusions and Relevance In this cohort study of women with a family history of breast cancer, DBT screening reduced recall rates and increased specificity compared to DM, particularly in women with 1 first-degree relative with breast cancer and those with scattered fibroglandular breast density, and reduced advanced cancer rates in women with extremely dense breasts.