EXAMINING BACKGROUND PARENCHYMAL ENHANCEMENT AS A NOVEL BIOMARKER FOR BREAST CANCER RISK IN BLACK WOMEN

Although breast cancer mortality rates have declined over recent decades, it remains the second leading cause of cancer death among women in the United States. Stark racial disparities persist, with Black women more likely than White women to be diagnosed at later stages and with more aggressive tumor subtypes. Early detection is critical to reducing these disparities. Women with dense breasts benefit from supplemental screening with breast magnetic resonance imaging (MRI) or ultrasound, as breast density—the proportion of fibroglandular to fatty tissue—can obscure tumors on mammography. Additionally, reast density is a moderate-to-strong risk factor, showing a clear dose-response relationship with invasive breast cancer incidence.In Aim 1, we found that relying on breast density to guide supplemental screening may disadvantage Black women, who are statistically less likely to have dense breasts and therefore less likely to qualify for additional imaging. This finding highlights the need to identify more equitable biomarkers of breast cancer risk for Black women. In Aims 2 and 3, we investigated background parenchymal enhancement (BPE)—the enhancement of normal breast tissue following contrast administration on MRI—as a potential alternative biomarker. BPE has shown promise as a stronger imaging biomarker of breast cancer risk than breast density, yet its utility has not been studied in Black women. In Aim 2, we evaluated radiologist-assessed BPE, while in Aim 3, we used a novel quantitative measurement. Across both BPE measurements, we found that Black women were more likely than White women to exhibit higher BPE levels, even after adjusting for known breast cancer risk factors. Mediation analyses revealed that differences in breast density, menopausal status, age, and BMI did not fully explain the racial disparities in BPE. Our work provides preliminary data to further examine whether novel imaging biomarkers, such as BPE, can more equitably improve supplemental screening approaches for breast cancer.