Mammograms are an important tool for diagnosing breast cancer, but they can have their limitations. A new study published in Radiology says digital breast tomosynthesis, or DBT, can help with some of those limitations, as it can be better at detecting cancer and produce fewer false negatives.
DBT is performed with an X-ray camera moving in an arc over the breast, capturing images from different angles. These are processed into 3-D-like images that can be viewed one millimeter at a time. This can help address the problem of cancers being hidden in overlapping tissue and the need for more imaging with regular mammograms.
Dr. Melissa Durand is the study’s lead author and associate professor of diagnostic radiology and biomedical imaging at Yale University School of Medicine and Smilow Cancer Hospital in New Haven, Connecticut. She explained that DBT is more like combing through the breast tissue, rather than looking at flat images of it.
Durand and other researchers compared the performance of DBT and digital mammography by looking at more than 380 thousand screening exams. They examined the rates of false negative screening examinations, or cancers that were found within a year of a regular mammogram. False negative cancers tend to be more aggressive than those detected during screening, so lowering those numbers could be better for preventing advanced disease or death.
The analysis found that DBT screenings improved sensitivity and specificity for breast cancer and identified more invasive cancers with fewer instances of spreading into lymph nodes or other parts of the body.
Dr. Durant noted the importance of this, saying, “”Our results build on past studies that have shown that DBT improves performance outcomes for breast cancer screening. 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.”
DBT screening also led to fewer overall false negatives and symptomatic false negatives.
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In addition, it provided benefits for women with dense breasts, which are more prone to cancer and also make things more difficult for detection. Recall rates were lower for both mostly dense and extremely dense breast tissue, and there were higher detection rates in both, as well.
Dr. Durand says these findings will likely help further DBT’s increased use over digital mammography. She explains, “Together with reduced recall rates and, thus, less patient anxiety, I would anticipate that DBT will continue to move forward as the standard of care to replace regular mammography.”
The American Cancer Society noted in a 2019-2020 breast cancer report that while DBT was approved by the FDA in 2011 and has been shown in some studies to have benefits over regular mammograms, it’s not yet available in all communities and may not be fully covered by insurance. It’s also not yet known how it impacts survival numbers.