Digital mammography (DM) has long been the mainstay of screening for breast cancer to detect early cancerous changes and is effective in improving BC detection.¹ A recent retrospective study on digital breast tomosynthesis (DBT) has found that DBT is associated with improved screening mammography outcomes in comparison to DM.²

According to the American Cancer Society (ACS) in 2022, breast cancer is the most commonly diagnosed cancer among women in the United States (US), following non-melanoma skin cancer, and is one of the leading causes of female cancer death.³ The high diagnostic rate is likely due to the effective screening program for breast cancer, such that there is a high detection of asymptomatic disease.³ However, false positives from DM should also be taken into account.⁴ Mammography with tomosynthesis has been shown to decrease false positive detection rates significantly, resulting in more accurate detection of breast cancer, and is deemed as a more efficient breast screening method.⁴ STORM was another prospective population-screening study which showed that 3D DM with tomosynthesis improved the detection of breast cancer.⁵ With the established benefits of DBT, the study by Conant et al. further proved its practical benefits in a larger population.²

The retrospective study consisted of 2,528,063 women, aged 40-79 years, without a history of BC on or before a previous screening mammogram that was taken at least once between January 2014 through December 2020, and that they were split into the DM and DBT cohorts.²  The primary outcomes included recall rates (RRs), cancer detection rates (CDRs), positive predictive value of recall (PPV1), biopsy rate, and positive predictive value of biopsy (PPV3).²  The mean age of participants at screening was 57 ± 10 years [± standard deviation (SD)] in both the DM and DBT groups.²

The results showed that there was a lower crude RR of 8.9% (95% CI: 8.9-9.0) in the DBT group as compared with the DM group (RR=10.3%; 95% CI: 10.3-10.4; p<0.001).² Upon adjustment for potential confounders such as extremely dense breast tissue, DBT was associated with a lower RR [odd ratio (OR)=0.92; 95% CI: 0.91-0.93; p<0.001].² Overall, crude CDR was also greater in the DBT group, with 5.3 of 1,000 screening mammograms (95% CI: 5.2-5.5), than in the DM group, with 4.5 of 1,000 screening mammograms (95% CI: 4.3-4.6; p<0.001).² Upon confounding adjustment, DBT was significantly associated with a greater CDR than DM (OR=1.24; 95% CI: 1.19-1.30; p<0.001).² Crude PPV1 was also greater in the DBT group (5.9%; 95% CI: 5.7-6.0) than in the DM group (4.3%; 95% CI: 4.2-4.5; p<0.001).² Upon adjustment, DBT was still associated with greater PPV1 (OR=1.33; 95% CI: 1.27-1.40; p<0.001).²

The crude biopsy rate was 17.6 of 1,000 screening mammograms for the DBT group (95% CI: 17.4-17.8) and 14.5 of 1,000 for the DM group (95% CI: 14.2-14.7; p<0.001), with the association between DBT and the biopsy rate also being statistically significant in adjusted analyses (adjusted OR=1.33; 95% CI: 1.30-1.37; p<0.001).² On the other hand, there was no statistically significant association of PPV3 with DBT, such that the crude PPV3 was 29.3% (95% CI: 28.7-29.9) and 30.0% (95% CI: 29.2-30.9) in the DBT and DM groups, respectively (p=0.16).² This remained so even after adjustment (OR=0.95; 95% CI: 0.90-1.00; p=0.16).²

In summary, the retrospective cohort study has shown a lower RR and a greater CDR, PPV1 and biopsy when using DBT as compared with DM, even after adjustment for potential confounders.² This thus showed improved screening outcomes with DBT as compared with DM, of which data may be used for future research in the detection of advanced breast cancer or other subgroup analysis of DBT and DM.²