Breast Cancer Screening with Digital Breast Tomosynthesis Reduces Rates of False Negatives

A retrospective study found that breast cancer screening with digital breast tomosynthesis (DBT), compared to screening without DBT, improved sensitivity and specificity and reduced the rates of false negatives.

The use of DBT has been associated with improved breast cancer detection and recall rates, but its impact on survival is less clear. A false negative screening can have a significant impact on morbidity and mortality.

“With DBT, you can really feel like you’re combing through the breast tissue instead of just looking at flat pictures,” explained study lead author Melissa A. Durand, MD, associate professor of diagnostic radiology and biomedical imaging at Yale University School of Medicine and Smilow Cancer Hospital in New Haven, Conn., in a press release.

The study took place at 10 academic and community practices. Dr. Durand and her colleagues compared digital mammography screening examinations one year before DBT implementation and DBT screening examinations through June 30, 2013. They linked the examinations to cancers through June 30, 2014. Cancers identified after false negative examinations were classified as symptomatic or asymptomatic. Comparisons were made for false negative rates, sensitivity, specificity, cancer detection and recall rates, positive predictive values, tumor size, histologic features, and receptor profile.

“Using false negative cancer rates is a way to get an idea of how a tool can affect morbidity/mortality in a more reasonable time frame than a randomized clinical trial,” said Dr. Durand.

Final analysis included 380,641 screening examinations, stratified by DBT (n=183,989) and digital mammography examinations (n=196,652). DBT examinations trended toward lower rates of false negative examinations, with 0.6 per 1,000 screens compared to 0.7 per 1,000 screens for digital mammography (P=0.20), as well as symptomatic false negative examinations (0.4 per 1,000 screens vs. 0.5 per 1,000 screens, respectively; P=0.21). A trend was observed between asymptomatic false negative rates and dense breasts (DBT, 0.14 per 1,000 screens vs. DM, 0.07 per 1,000 screens; P=0.07).

“With women who have extremely dense breasts, the cancer detection was higher, but not significantly so, which makes sense, ” Dr. Durand explained. “You need a bit of fat to provide contrast to the fibroglandular tissue in order to detect abnormalities, whether you are using DBT or digital mammography. This highlights a group of women who would benefit from supplementary screening.”

DBT, compared to digital mammography, improved sensitivity (89.8% [966/1076 cancers] vs. 85.6% [789/922 cancers]; P=0.004) and specificity (90.7% [165,830/182,913 examinations] vs. 89.1% [174,480/195,730 examinations]; P<0.001). Cancers identified in DBT examinations were more likely to be invasive (P<0.001), have fewer positive lymph nodes (P=0.04), and have distant metastases (P=0.01), and were less likely to have a false negative finding of advanced cancer (odds ratio, 0.9; 95% confidence interval, 0.5-1.5).

“Our results build on past studies that have shown that DBT improves performance outcomes for breast cancer screening,” Dr. Durand stated. “With DBT, we show we are detecting more invasive cancers, but they are cancers with favorable prognostic criteria, which means these patients would have more treatment options.”

The study was published in Radiology.