Purpose: Breast MRI background parenchymal enhancement (BPE) has been identified as a risk factor for breast
cancer and has been associated to certain tumor characteristics. However, it is not known whether its presence is
related to tumor aggressiveness in high risk screening patients. The purpose of this study is to evaluate this
association between BPE and tumor grade in high risk screen detected breast cancers.
Methods and Materials: Review of our intermediate and high risk screening program from 2003A-A?A 1/2 2013 identified MRIscans
of 80 cancers in 79 patients (48A-A?A 1/2 9.8 years) with biopsy proven unilateral cancer and no previous breast cancer.
The level of BPE in the contralateral breast was scored as minimal, mild, moderate, and marked by two readers (one
5th year resident (R1) and one experienced radiologist (R2)). Odds ratios (OR) were calculated for grade in relation to
BPE. Observer variability was computed using kappa statistics.
Results: A significant association was found between tumor grade and level of BPE in the contralateral breast for both
readers (the OR for high grade tumor was 0.394 (p=0.007) for R1 and 0.310 (p=0.002) for R2). After adjusting for
significant factors, the OR for high grade cancers was 0.924 for R1 and 2.066 for R2. Kappa value for BPE
assessment between readers was K=0.592.
Conclusion: Lower BPE might be associated to higher tumor grade, when only evaluating BPE. However, our results
suggest that other factors play a major role in this association. This limits the usefulness of BPE as a parameter for