TOPLINE

In a retrospective study, higher quantitative background parenchymal enhancement (BPE) on breast MRI was associated with increased cancer risk among women with BRCA1/2 mutations — suggesting BPE could help refine risk assessment.

METHODOLOGY

• BPE on dynamic contrast-enhanced MRI enables physiologic assessment of hormonally responsive glandular tissue and has emerged as a potential biomarker for breast cancer risk that may be stronger than mammographic density. But its utility among women with BRCA mutations is unclear.
• To investigate, researchers conducted a retrospective study involving 385 women with BRCA1/2 pathogenic variants who had 1278 breast MRIs performed between 2002 and 2022 at the University of Pennsylvania, Philadelphia.
• Quantitative BPE measures included median BPE and the proportion of fibroglandular tissue voxels with over 20% enhancement (BPE20/FGT), calculated using fully automated methods from dynamic contrast-enhanced MRI scans.
• The primary outcome was incident breast cancer diagnosed at least 6 months after MRI. Repeated-measures proportional hazards models assessed associations of BPE with cancer risk, adjusting for age, menopausal status, volumetric breast density, BMI, and BRCA type.

TAKEAWAY

• During follow-up, 39 women developed breast cancer. The BPE20/FGT ratio was associated with increased breast cancer risk in the fully adjusted model (hazard ratio [HR], 1.13; P < .005), with the HR reflecting risk per 10-unit increase.
• In axial MRI images only, the association was stronger for BPE20/FGT (HR, 1.34; P < .005 in the fully adjusted model) and median BPE (HR, 1.30; P < .005).
• There were 53 women who had at least one MRI before and after undergoing oophorectomy. Their BPE measures showed a statistically significant decrease after surgery, with a median change in median BPE of -1.6 (P = .03) and median change in BPE20/FGT of -7.7% (P = .01), representing approximately 24% reduction for both measures.
• The BRCA2 group had higher BPE than the BRCA1 group, with a higher median BPE (12.5 vs 10.9, P = .04) and higher median BPE20/FGT ratio (35.5 vs 31.3, P = .05) at the first MRI.

IN PRACTICE

“Our results suggest that BPE is a promising dynamic and modifiable risk marker among mutation carriers that could be used to tailor prevention strategies,” the study authors wrote. Future studies, they added, should look at whether BPE can signal residual cancer risk after oophorectomy, potentially “yielding important information for screening and prevention.”

SOURCE

The study, led by Alex A. Nguyen, University of Pennsylvania, was published online in Cancer Epidemiology, Biomarkers & Prevention.

LIMITATIONS

The relatively small number of breast cancers limited statistical power to detect associations and perform stratified analyses. BPE was only associated with breast cancer risk in axial orientation images, not sagittal images, possibly due to less accurate BPE calculation algorithms for sagittal scans. The study population included only women with no history of breast cancer and available breast images, potentially limiting generalizability.

DISCLOSURES

The study was supported by grants from the American Cancer Society and the University of Pennsylvania Basser Center for BRCA. A co-author reported receiving grants from the Breast Cancer Research Foundation during the conduct of the study. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.