Effect of Background Parenchymal Enhancement on Cancer Risk Across Different High-Risk Patient Populations Undergoing Screening Breast MRI

OBJECTIVE. The purpose of this study is to evaluate the effect of background parenchymal enhancement (BPE) on breast cancer risk across different high-risk patient populations undergoing screening breast MRI. MATERIALS AND METHODS. Consecutive screening breast MRI examinations performed between 2011 and 2014 were reviewed. Multivariate logistic regression using generalized estimating equations was used to assess the association of the following variables with cancer risk age, qualitative BPE prospective clinical assessment (minimal or mild vs moderate or marked), mammographic breast density (dense vs not dense), and screening indication (prioritized in the following order: BRCA carrier or history of thoracic radiation, breast cancer personal history, high-risk lesion, and breast cancer family history). Cancer diagnosis was defined as a tissue diagnosis of invasive or in situ carcinoma within 12 months of the screening MRI. RESULTS. The study cohort included 4686 screening MRI examinations performed in 2446 women, grouped by BPE as minimal or mild (3975/4686; 85%) versus moderate or marked (711/4686; 15%) and by screening indication as BRCA carrier or history of thoracic radiation (548/4686; 12%), breast cancer personal history (2541/4686; 54%), high-risk lesion (362/4686; 8%), and breast cancer family history (1235/4686; 26%). After adjustment for confounding variables, only BPE and screening indication were independent predictors of cancer diagnosis (p = 0.02 and p < 0.01, respectively). The odds ratio for developing cancer in the moderate or marked BPE group compared with the minimal or mild group was 2.1 (95% CI, 1.1-40), after adjusting for age, breast density, and screening indication. CONCLUSION. Increased BPE level is an independent predictor of breast cancer in women undergoing screening MRI for different high-risk indications.