Correlation of quantitative background parenchymal enhancement with prognostic factors in breast cancer.

OBJECTIVES: To semi-automatically quantify background parenchymal enhancement (BPE) in the contralateral healthy breast of patients with unilateral invasive breast cancer and investigate its correlation with prognostic factors, aiming to provide an imaging-based basis for breast cancer prognostic assessment. MATERIALS AND METHODS: A retrospective analysis was conducted on 124 patients with pathologically confirmed unilateral invasive breast cancer treated at Shenzhen Longgang Central Hospital between January 2019 and December 2024, BPE in the unaffected breast was quantified semi-automatically from DCE-MRI (phase 2 post-contrast) using 3D Slicer software (v5.6.2). Associations between quantitative BPE and prognostic factors (menopausal status, axillary lymph node metastasis, BMI, molecular subtype [Luminal A, Luminal B, HER-2+, triple-negative], ER, PR, HER-2, Ki-67) and systemic biomarkers (age, NLR, LMR, SII) were assessed using Mann-Whitney U, Kruskal-Wallis H, and Spearman's correlation tests. RESULTS: Quantitative BPE showed no significant differences based on menopausal status, axillary lymph node status, ER/PR/HER-2 status, BMI category, or molecular subtype (all P > 0.05). No significant correlations were found with age, NLR, LMR, or SII (all P > 0.05). Significantly lower BPE was observed in the Ki-67 high-expression group compared to the low-expression group (P = 0.002). CONCLUSION: Our study found that quantitative background parenchymal enhancement (BPE) was significantly lower in the Ki-67 high-expression group than in the low-expression group, suggesting a negative association with tumor proliferative activity. In addition, a certain correlation was also observed between BPE and the systemic inflammatory marker PLR. These findings provide preliminary clues for exploring BPE as an adjunctive imaging biomarker.