The newer, 3D form of breast screening, known as digital breast tomosynthesis (DBT), is more effective at detecting breast cancer than traditional 2D digital mammography (DM). That's the conclusion of an analysis of 13 years' worth of screening data conducted by Yale Cancer Center researchers. The data also suggests that 3D mammograms could reduce the incidence of advanced cancer diagnoses.
"Most of the time, women will do better with 3D mammograms since their cancers are being caught sooner," said co-first author Dr. Liane Philpotts, a professor of radiology and biomedical imaging at Yale School of Medicine (YSM) and a member of Yale Cancer Center.
The study results were published in Radiology, a journal of the Radiological Society of North America, on Sept. 17.
DBT reconstructs pictures of the breast taken from different angles into 3D images, whereas DM makes pictures of the breast from two angles. YSM radiologists at Yale New Haven Health (YNHH) adopted the new DBT technology in 2011.
Researchers analyzed 1,407 breast cancer cases detected from August 2008 to July 2021, including 35,544 DM screenings and 237,394 DBT screenings. Researchers compared a range of data, such as patient demographics, imaging results, and pathology reports.
Results showed that DBT had a higher rate of cancer detection than DM (5.3 versus 4 per 1000 screenings) without leading to overdiagnosis of less harmful cancers that shouldn't impact a patient's life.
Also, the false positive recall rate (when a woman undergoes additional testing after a screening finds a non-cancerous abnormality in her breast) was significantly less for DBT at 7.2% compared with 10.6% for DM.
Philpotts says fewer false positives and the overall higher cancer detection rate is a win-win and shows DBT is not over-diagnosing cancers.
"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."
A randomized clinical trial to assess the impact of DBT is ongoing. Philpotts added that she would like to see other long-term studies that compare DBT and DM. She hopes this retrospective study provides data useful to health care institutions still considering the new screening technology.
Jaskirandeep Kaur Grewal, a former student in the Yale School of Medicine Physicians Associate Program, joined Philpotts as co-first author on the study.
