Breast cancer screening has taken another step forward with the conclusion of an analysis of 13 years of data conducted by Yale Cancer Center researchers.

They found that digital breast tomosynthesis (DBT), a newer, 3D form of breast screening is more effective at detecting breast cancer than the 2D mammograms produced by traditional digital mammography (DM). The findings also suggest that 3D mammograms could reduce the incidence of late diagnoses of advanced cancers.

DBT or digital breast tomosynthesis is a form of mammography that reconstructs pictures of the breast taken from different angles into 3D images. DM or digital mammography makes pictures of the breast from only two angles.

“Based on the results, DBT is an effective screening tool that not only finds more cancers, it catches them earlier at a lower stage, which means fewer advanced cancers.”

The researchers analyzed 272,938 screening mammograms done from August 2008 to July 2021. Over 35,500 were performed using traditional digital mammography, and 237,394 were performed using DBT.

The DBT data included 10 years of DBT mammograms, which became the standard at Yale facilities beginning in 2011. The DM data encompassed three years of mammograms performed with digital mammography before DBT became the standard.

Researchers compared a range of data, such as patient demographics, imaging results and pathology reports.

A total of 1,407 cancers were detected: 142 by mammography and 1,265 by DBT.

DBT's higher detection rate yielded 5.3 cancers per 1000 screenings, versus 4 for DM. DBT also did not lead to overdiagnosis of less harmful cancers that were unlikely to impact a patient's life.

“Overdiagnosis has been a hot topic in mammography screening,” Liane Philpotts, M.D., co-first author and a professor of radiology and biomedical imaging at Yale School of Medicine, said in a statement. “Skeptics of mammography screening believe that the use of DBT results in overdiagnosis.”

“We found that digital mammography and DBT screening mammography found the same types of cancers, but at different stages,” she added. “DBT found more aggressive cancers at an earlier stage compared to digital mammography.”

DBT not only had a higher cancer detection rate than traditional mammography — 5.3 percent for DBT compared to 4 percent for DM; it had a lower rate of advanced cancers — 32.7 percent versus 43.6 percent — indicating that cancers are seemingly being detected earlier.

“Based on the results, DBT is an effective screening tool that not only finds more cancers, it catches them earlier at a lower stage, which means fewer advanced cancers,” said Philpotts. “And over time, when women have repeated 3D mammograms, the number of advanced cancers diagnosed is even lower.”

Digital breast tomosynthesis is becoming more widely available. “About 90 percent of certified mammography facilities in the U.S. are now DBT,” Philpotts, also on the staff of the Yale Cancer Center, told TheDoctor in an email. “This has increased precipitously over the last few years.”

Except for those living in certain rural or remote locations, most women in the U.S. will have access to DBT, Philpotts added. “In other areas of the world DBT is not the standard of care and studies such as ours are important for supporting the switch to 3D over 2D.”

When scheduling a mammogram appointment, Dr. Philpotts recommends that you check to see if the facility has DBT. Some facilities may offer both, so it's a good idea to ask.

The study is published in Radiology, a journal of the Radiological Society of North America (RSNA).