A higher level of background parenchymal enhancement (BPE) measured during breast MRI is associated with the presence of breast cancer in women with high risk but not in women with average risk, reveals a study published online June 25 in Radiology.
For the study, Christopher Thompson of Texas Tech University and colleagues sought to evaluate, separately, the association between qualitative and quantitative BPE at dynamic contrast material–enhanced MRI and breast cancer in women at average risk and high risk for the disease. Their rationale in doing so: A higher level of BPE at breast MRI has the potential for early detection and prediction of breast cancer risk, but conflicting findings about the association between the level of BPE at breast MRI and the presence of breast cancer have previously been reported.
The researchers conducted a retrospective meta-analysis of 18 observational studies comparing either qualitative or quantitative assessments of BPE in women with and without breast cancer. Performed before July 2018, the studies comprised a collective 1,910 breast cancer patients, along with 2,541 control participants.
Studies were eligible for inclusion the meta-analysis only if they had originally been published in the English language; were conducted in human patients; and contained both a case group of participants with breast cancer and a control group of participants without breast cancer.
Eligible studies also had to include BPE measurements, either in qualitative data (minimal, mild, moderate, marked) evaluated by a radiologist using the BI-RADS lexicon or quantitative data (in cubic centimeters and/or in BPE percentage), obtained from dynamic contrast-enhanced MRI. Review articles, case reports or case series, replies to study authors, studies published only in abstract form, and studies without the necessary data for meta-analysis were excluded from consideration.
From the meta-analysis, Thompson et al determined that among women with a high risk of breast cancer, at least moderate BPE (OR, 1.6) or at least mild BPE was associated with higher odds of developing the disease. Women with breast cancer were discovered to have a higher average BPE percentage compared with control participants in the high-risk category. The researchers identified no association between at least mild BPE level or at least moderate BPE level and the presence of breast cancer among the population of women with average risk of developing breast cancer.
“An interesting question that remains unclear from our study is whether higher BPE is associated with all cancers or with a specific subtype of cancer separately for women with high risk and for women with average risk,” the authors wrote. Nonetheless, “a higher level of background BPE is associated with the presence of breast cancer in women with high risk (and) perhaps, changes in quantitative BPE over time could be a potential metric for detecting future risk of breast cancer.”
Thompson and colleagues added that because the meta-analysis did not confirm a significant association “between a higher level of BPE and the presence of breast cancer among women with average risk,” a standardized protocol for BPE measurement that follows a uniform format for recording BPE data, preferably in a quantitative form, might be introduced. “This incorporation may improve the reliability and interpretation of BPE data,” they concluded. “A large multicenter longitudinal study is warranted to confirm the association of higher BPE values measured by using breast MRI and changes in BPE values for predicting the risk of developing breast cancer.”