Boston Breast Imaging
Educational Hub
Case 11
(continued)
Answer:
Normal glandular tissue of the breast takes up contrast material to variable degrees which is called background parenchymal enhancement (BPE).
BPE is classified similarly to breast MRI as minimal, mild, moderate, and marked. This case is an example of minimal BPE.
Why do we care about BPE on contrast-enhanced mammography?
There are a few reasons. (1) Does BPE impact how well we find cancers? If there is more BPE, is it harder to find cancers, lowering the sensitivity of CEM?
No studies have clearly shown this yet. Our understanding largely is based on MRI, for which there is conflicting results. More recent data suggests that while increased BPE does impact abnormal interpretation rates (call-back, false positive) it doesn't impact cancer detection rates. (2) If BPE does reduce cancer detection, then what can we do to minimize it? A few published studies have shown that higher levels of BPE are associated with dense breast tissue and premenopausal status. BUT, the studies do not show a significant relationship of BPE to days since last menstrual period. So for now, there is not much we can do. It does appear that BPE is less in women who are taking endocrine therapy. (3) Are higher levels of BPE associated with increased risk of developing cancer? A good study assessing this hasn't been performed yet. There does seem to be an association on MRI, but this hasn't been shown yet with CEM.
Karimi Z, Phillips J, Slanetz P, et al. Factors Associated With Background Parenchymal Enhancement on Contrast-Enhanced Mammography. AJR Am J Roentgenol. 2021 Feb;216(2):340-348
Sogani J, Morris EA, et al. Comparison of Background Parenchymal Enhancement at Contrast-enhanced Spectral Mammography and Breast MR Imaging. Radiology. 2017 Jan;282(1):63-73
Dontchos BN, Rahbar H, Partridge SC, et al. Are Qualitative Assessments of Background Parenchymal Enhancement, Amount of Fibroglandular Tissue on MR Images, and Mammographic Density Associated with Breast Cancer Risk? Radiology. 2015 Aug;276(2):371-80.
Hambly NM, Liberman L, Dershaw DD, et al. Background parenchymal enhancement on baseline screening breast MRI: impact on biopsy rate and short-interval follow-up. AJR Am J Roentgenol. 2011 Jan;196(1):218-24.