DBT detects earlier stage breast cancers in older women

In women 65 and older, digital breast tomosynthesis (DBT) achieved a higher specificity for detecting breast cancer and identified the disease at an earlier stage compared to traditional 2-D mammography, according to a study of more than 35,000 women published in Radiology.

Researchers from Massachusetts General Hospital (MGH) in Boston compared the 2D digital mammograms of more than 15,000 women (mean age 72.7 years) to those of more than 20,000 women (mean age 72.1) who received breast cancer screening via DBT.

Importantly, the researchers noted, each modality was effective at detecting breast cancer, but DBT outperformed in a few areas. DBT yielded a higher positive predictive value (14.5 percent vs. 11.9 percent), a higher specificity (95 percent vs. 94.8 percent) and resulted in fewer false-positive exams.

"We've shown that screening mammography performs well in older women, with high cancer detection rates and low false-positives, and that tomosynthesis leads to even better performance than conventional 2-D mammography," said study lead author Manisha Bahl, MD, MPH, radiologist at MGH and assistant professor of radiology at Harvard Medical School, in an RSNA news release.

The team also noted DBT had a lower abdominal detection rate and that the modality detected less lymph node-positive cancers (10.2 percent vs. 16.6 percent), a potential sign the method can detect cancers earlier, the authors wrote.

“Detecting breast cancers at an early stage is the goal of screening mammography,” Bahl added.

In a related editorial, Liane E. Philpotts, MD, and Melissa A. Durand, MD, both with Yale School of Medicine, New Haven, Connecticut, commended the study, writing the results were a “vital step in a more effective and personalized approach to screening.”

The Yale researchers also pointed out the importance of DBT’s ability to detect earlier stage cancers, particularly in older populations.

“Finding fewer cancers that have spread to lymph nodes translates to better prognosis and less aggressive treatment, an important consideration for an older woman,” the authors wrote. “Because aggressive treatment may be impractical or cause considerable morbidity or mortality in an older woman, the detection of lower-stage disease is an important benefit.”

The FDA approved DBT for breast cancer screening in 2011, and it has since become widely used as a supplement for digital mammography. However, the benefits of screening for older women remains a subject of debate, and the United States Preventive Services Task Force currently recommends screening mammography only until the age of 74.

While the results of this study don’t support a specific age cutoff date, according to Bahl, such guidelines should be based on individual factors and preferences.