Pairing DBT with synthetic 2D mammography finds more cancers than digital mammography alone

The combination of digital breast tomosynthesis (DBT) and digital mammography (DM) can detect more breast cancers than DM alone, but researchers have also noted a variety of issues with that pairing. According to a new study published in Radiology, however, using DBT and two-dimensional synthetic mammography (SM) together detects more cancers than DM.

The authors analyzed data from more than 98,000 women screened in Norway in 2014 and 2015. Overall, more than 37,000 women screened with DBT and SM, and more than 61,000 women were screened with DM alone. The pairing of DBT and SM was found to have a higher rate of screen-detected cancer than DM (9.4 per 1,000 patients screened versus 6.1) and a higher rate of detecting tumors 10 mm or smaller (more than three per 1,000 patients versus 1.8).

“We identified a significantly higher rate of screen-detected breast cancer in women screened with DBT and SM than in women screened with DM in the Norwegian Breast Cancer Screening Program,” wrote lead author Solveig Hofvind, PhD, of the Oslo and Akershus University College of Applied Sciences in Oslo, Norway, and colleagues. “The incremental cancer detection rate was higher for both DCIS and invasive breast cancers.”

Recall rates for the two breast screening methods were almost identical (3.4 percent for DBT and SM, 3.3 percent for DM), but DBT and SM were found to have a higher positive predictive value of recalls (PPV-1) and a higher positive predictive value of performed needle biopsies (PPV-3).

“Similar recall rates for screening with DM and for screening with DBT and SM, combined with a higher value of both PPV-1 and PPV-3 for screening with DBT and SM, may indicate that screening with DBT and SM is a more effective screening tool than screening with DM,” the authors wrote.

The authors added that there is still much more work to be done in the evaluation of these screening methods.

“A future investigation with long-term clinical follow-up data is needed to determine differences in the rate of interval breast cancer, differences in tumor characteristics, and differences in survival data for screening with DBT and SM compared with screening with DM,” they wrote.