Breast MRI shows higher BPE levels in Black women

Black women show higher levels of background parenchymal enhancement (BPE) on contrast-enhanced breast MRI, despite tending to have lower breast density levels, researchers have reported.

The findings highlight the limitations of the Breast Imaging Reporting and Data System (BI-RADS) for breast density currently used in clinical practice and the complexities of how women qualify for supplemental MRI as part of a breast cancer screening or diagnostic workup, according to a team led by MD/PhD candidate Mattia Mahmoud of the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. The study was published January 13 in Radiology.

"Current screening guidelines rely heavily on breast density as assessed via mammography and risk models that often provide underestimations for Black women," the group noted. "BPE is an MRI sign that reflects hormonally active breast tissue and has emerged as an independent predictor of breast cancer risk."

BPE is evaluated qualitatively by radiologists using BI-RADS categories of minimal, mild, moderate, and marked, but it is subject to interreader variability, according to the authors. Studies have suggested a positive association between increasing ordinal levels of BPE and breast cancer risk, regardless of breast density, they added. Identifying BPE involves the intravenous administration of gadolinium-based contrast agents and an MRI scan to identify areas of vascular enhancement in breast tissue.

To explore the extent to which breast density may account for racial differences in BPE, Mahmoud and colleagues conducted a study that included data from a group of 388 Black women and 2,101 white women without a history of breast cancer. The women (mean age, 47 and 48, respectively) underwent both screening mammography and subsequent screening or diagnostic MRI at one of four sites within the University of Pennsylvania health system between 2016 and 2023.

According to the results, while the proportions of both groups exhibiting high BPE at breast MRI were similar (38% vs. 33%; p = 0.11), Black women were 31% more likely to have high BPE levels after density differences were eliminated (odds ratio [OR], 1.31; p = 0.04).

"Our study on Black-white racial differences in qualitative background parenchymal enhancement (BPE) revealed that Black women have 31% greater odds of having high BPE than white women, despite the positive association between BPE and breast density, even after we adjusted for well-known breast cancer risk factors," Mahmoud and colleagues explained, acknowledging that there is limited information on the specific pathophysiology of BPE.

The researchers also highlighted that only 1% to 5% of all U.S. women who undergo breast imaging also undergo breast MRI.Examples of (A) minimal, (B) mild, (C) moderate, and (D) marked clinical background parenchymal enhancement (BPE) on subtracted postcontrast maximum intensity projection images.RSNA

"It is important to interpret our findings as reflecting differences in BPE levels among women who received breast MRI, rather than in the general population," Mahmoud and colleagues wrote, adding that their preliminary data warrants further investigation of the degree of clinical BPE in Black women and whether imaging markers such as BPE, can be used for better breast cancer risk prediction among Black women.

Find the complete paper here.