DBT offers ‘significantly increased’ cancer detection compared to digital mammography

Digital breast tomosynthesis (DBT) yields much higher cancer detection rates compared to digital mammography, reported authors of a retrospective study published Oct. 16 in the American Journal of Roentgenology.

The findings were true regardless of tumor type, size or cancer stage, wrote Pragya A. Dang, MD, and colleagues at Brigham and Women’s Hospital in Boston.

“Prior studies have shown mixed results regarding overall (cancer detection rates) CDRs and detection rates of invasive cancers with DBT when compared with FFDM, with some reporting significant increase in CDRs and others showing no differences,” Dang and co-authors explained. “Our results suggest that integrating DBT into clinical practice may detect overall more cancers than does FFDM, for all tumor sub-types, grades, sizes and nodal statuses.”

DBT has gained popularity due to many reports of its improved detection of breast cancer in women with dense breasts and its 2011 FDA-approval. However, a majority of centers have been slow to adopt the modality, and industry groups have disagreed about DBT’s role in screening. The American College of Radiology and American Society of Breast Surgeons have both expressed their support for DBT screening.

For their study, the researchers reviewed consecutive screening, full-field digital mammography (FFDM) and DBT exams performed between October 2012 and September 2014. A total of 61 cancers were detected in the matched cohort of 9,817 DBT exams and 14,180 FFDM scans.

Compared to FFDM, DBT produced a higher detection rate for invasive cancers (2.8 vs. 1.3), minimal cancers (2.4 vs 1.2), estrogen receptor-positive invasive cancers (2.6 vs. 1.1) and node-negative invasive cancers (2.3 vs. 1.1).

The detection rate between the two modalities was not significantly different for screen-detected invasive cancers to ductal carcinoma in situ, the authors noted. This may have been due to the smaller number of cancers in those subgroups.

Dang and colleagues cautioned that the results may not be applicable to other institutions and explained the CDRs in both the FFDM and DBT subgroups are lower than the benchmarks created by the Breast Cancer Surveillance Consortium.

“Larger prospective studies are warranted to validate these results and investigate long-term outcomes of DBT screening for breast cancers, particularly invasive cancer,” the researchers concluded.