Images in 71-year-old woman with 1.6-cm invasive ductal carcinoma (Breast Imaging Reporting and Data System category 5, with category C breast density). Low-energy mammogram and corresponding regions of interest for mammogram (top) and breast tissue composition images (bottom two rows). CREDIT Radiological Society of North America.
A novel technique that uses mammography to determine the biological tissue composition of a tumor could help reduce unnecessary breast biopsies, according to a recent study (Drukker K et al Combined Benefit of Quantitative Three-Compartment Breast Image Analysis and Mammography Radiomics in the Classification of Breast Masses in a Clinical Data Set. Radiology. 2019; 290(3):621-628. doi: 10.1148/radiol.2018180608)
Research estimates the post-mammography recall rate for women to be more than 10 percent in the United States (although it is generally lower in Europe).
“The callback rate with mammography is much higher than ideal,” said the study’s first author, Dr Karen Drukker, “There are costs associated with recalls, and our goal is to reduce these costs but not miss anything that should be biopsied.”
Dr. Drukker and colleagues recently studied a new technique called three-compartment breast (3CB) imaging. By measuring the water, lipid and protein tissue composition throughout the breast, 3CB might provide a biological signature for a tumor. For instance, more water in the tumor tissue might indicate angiogenesis, For the study, the researchers acquired dual-energy mammograms from 109 women with breast masses that were suspicious or highly suggestive of a malignancy immediately prior to biopsy, and the ensuing biopsies showed 35 masses to be invasive cancers, while the remaining 74 were benign.
3CB images were derived from dual-energy mammograms and analyzed along with mammography radiomics, a method developed by Dr. Maryellen L. Giger and her team at the University of Chicago. The method uses artificial intelligence algorithms to analyze features and patterns in images. The combination of 3CB image analysis and radiomics improved the positive predictive value in breast masses deemed suspicious by the breast radiologist. The combined method improved PPV from 32 percent for visual interpretation alone to almost 50 percent, with an almost 36 percent reduction in biopsies. The 3CB-radiomics method missed one of the 35 cancers, for a 97 percent sensitivity rate.
“These results are very promising,” Dr. Drukker said. “Combining 3CB image analysis with mammography radiomics, the reduction in recalls was substantial.”
Dr. Drukker said the combined 3CB-radiomics approach has the potential to play an increasingly prominent role in breast cancer diagnosis and perhaps also screening. She noted that 3CB can easily be added to mammography without requiring extensive modifications of existing equipment.
“The patient is already getting the mammography, plus we get all this extra information with only a 10 percent additional dose of radiation,” she said.
The researchers plan to study how the combined approach will help radiologists make their final determinations. They also want to study the approach using digital breast tomosynthesis, which reduces the problem of overlapping breast tissue inherent to regular mammography. A tumor’s unique water-lipid-protein signature might be even clearer with tomosynthesis, Dr. Drukker said.