Molecular Breast Imaging Improves Cancer Detection in Women with Dense Breasts

A new multicenter study published in Radiology, the journal of the Radiological Society of North America (RSNA), reports that combining molecular breast imaging (MBI) with digital breast tomosynthesis (DBT) significantly improves invasive breast cancer detection in women with dense breast tissue, compared with DBT alone.

“This is the first multicenter, prospective evaluation of MBI as a supplemental tool to DBT in women with dense breasts,” said lead author Carrie B. Hruska, Ph.D., professor of medical physics at Mayo Clinic in Rochester, Minnesota.

According to the CDC, about 47% of women undergoing breast screening have dense breasts, which both raises breast cancer risk and makes mammograms less sensitive. DBT, a 3D mammography technique, improves imaging but still misses some cancers in dense tissue.

MBI, which uses a radiotracer to highlight metabolic activity in breast tissue, is one of several supplemental screening options alongside ultrasound, breast MRI, and contrast-enhanced mammography.

The Density MATTERS Trial (Molecular Breast Imaging and Tomosynthesis to Eliminate the Reservoir) evaluated the benefit of adding MBI to DBT.

• Study design: Women with dense breasts, aged 40–75, were enrolled across five sites between 2017 and 2022. They underwent two annual rounds of combined DBT and MBI, with one-year follow-ups through September 2024.
• Participants: 2,978 women (mean age 56.8 years), mostly postmenopausal, 82% with category C breast density, and 98% with no personal breast cancer history.

Dr. Hruska noted that 20% of MBI-only cancers were node-positive, underscoring its role in identifying clinically important disease.

The trial included both academic centers and community hospitals, such as MD Anderson Cancer Center, Henry Ford Health System, ProMedica Breast Care, and Mayo Clinic Health System in Wisconsin. Minority enrollment (12%) strengthened the generalizability of the results.

“Routine mammograms remain essential, but DBT does not find all cancers,” Dr. Hruska emphasized. “Women should understand the limitations and consider supplemental screening.”

She added that MBI is safe, cost-effective, well-tolerated, and uses a radiotracer long established in cardiac imaging. Unlike MRI or contrast-enhanced studies, MBI does not involve contrast reactions.

The study provides strong evidence that adding MBI to DBT improves detection of invasive and node-positive breast cancers in women with dense breasts, potentially reducing the number of women diagnosed with advanced disease during routine screening.