Abstract P3-02-08: Association of background parenchymal enhancement with breast cancer risk factors and tumor characteristics
Authors: Iyer L , Faramand R , Jung S , Rosenblatt P , Campassi C , Dromi S , Dorgan J , Tkaczuk K 
Published: May 2019

Abstract
Background: Background Parenchymal Enhancement (BPE) in a dynamic contrast enhanced (DCE)MRI refers to change in morphology and temporal degree of enhancement expressing physiology of breast tissue. Improvements in the analysis and interpretation of BPE have been shown to increase diagnostic accuracy of the MRI. We explored associations of BPE with breast cancer(BC) risk factors and tumor characteristics.
Methods: We conducted a retrospective chart review study of 149 women who were treated for BC at the University of Maryland Medical Center(UMMC) between 2003-2015. Institutional Review Board approval was obtained. Subjects had BI-RADS 4,5 or 6 on their mammograms and/or biopsy proven BC. Women with false positive mammograms (n=2), missing BPE grade in their MRI reports (n=6), metastatic BC at diagnosis (n=2), MRIs done outside of a year of diagnosis (n=3), and who followed up outside UMMC (n=1) were excluded. Final analysis included 135 women. We used 1.5T or 3T scanners for DCE MRI. Standard contrast enhanced MRI protocol, T1, T2, and dynamic series were acquired according to American College of Radiology requirements for breast MRI accreditation and interpreted with Maximum Intensity Projection and subtracted imaging. Fellowship-trained breast imagers performed qualitative BPE assessment as per standard BI-RADS classification. BI-RADS classes were grouped as high BPE (BI-RADS moderate and marked) and low BPE (BI-RADS minimal and mild). Multivariable logistic regression was used to assess associations with predictors including individual and tumor characteristics.
Results: Preliminary analyses showed BPE was significantly associated with alcohol intake, with drinkers being more likely to have high BPE compared to non-drinkers [odds ratio (OR) =3.08 (95% confidence interval (CI) = 1.34-7.09; p=0.008]. Women who received adjuvant radiation for their BC were less likely to have high BPE compared to women who did not undergo radiation [OR= 0.37 (95% CI=0.15-0.90); p=0.03] implying higher likelihood of breast conservation surgery in the former group. High BPE was less often observed for invasive ductal carcinoma histology vs. in-situ ductal carcinomas [OR= 0.40 95% CI=0.16-1.00); p=0.05] and in post- vs. premenopausal women [OR=0.47 (95%CI=0.22-1.00); p=0.05]. No association was found between BPE and race, BMI, prior HRT/OCP use, smoking, or ER/PR/HER-2 status.
Conclusion: We observed association between higher BPE and alcohol exposure and lower BPE and, invasive ductal histology, postmenopausal status at diagnosis of BC and adjuvant radiation for BC. Larger studies are needed to corroborate our findings and identify the underlying mechanisms.
Citation Format: Iyer L, Faramand R, Jung S, Rosenblatt P, Campassi C, Dromi S, Dorgan J, Tkaczuk K. Association of background parenchymal enhancement with breast cancer risk factors and tumor characteristics [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-02-08.