Abstract P4-01-04: MRI enhancement in stromal tissue surrounding breast tumors: Association with RFS following neoadjuvant chemotherapy

Objective: Stromal tissue surrounding breast tumors can harbor abnormalities that predict increased risk of recurrence. The purpose of this study was to evaluate low-level contrast enhancement patterns in normal appearing breast stroma surrounding tumors using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). A secondary objective was to investigate whether enhancement patterns varied with distance from tumor and whether proximity-dependent enhancement was associated with recurrence-free survival following neoadjuvant chemotherapy (NACT). Materials and Methods: Sixty-three patients with locally-advanced breast cancer were imaged with DCE-MRI before (V1) and after one cycle (V2) of adriamycin-cytoxan (AC) therapy. Normal-appearing stromal tissue on MR images was defined as fibroglandular tissue outside of tumor regions. Fibroglandular tissue was segmented from pre-contrast T1-weighted images using a fuzzy C-means clustering method 1 . Tumor regions were identified using a percent enhancement threshold of 70% in the first post-contrast image (PE1). Distance from tumor (proximity) was defined for each stromal voxel as the minimum three-dimensional distance from any tumor voxel. Stromal enhancement was characterized by calculating mean PE and mean signal enhancement ratio (SER = PE1/PE2) in distance shells of 5 mm, from 0 to 40 mm outside of tumor tissue. Global PE and SER were calculated by averaging all stromal voxels from 5 to 40 mm from tumor. Proximity-dependent PE and SER were analyzed using a linear mixed effects model and Cox proportional hazards model for recurrence-free survival. Results: The mixed effects model displayed a decreasing radial trend in PE at both V1(estimated mean = −0.39 per mm, 95% CI (−0.50, −0.29), p Conclusions: These findings show that stromal tissue outside the primary tumor can be quantitatively characterized by DCE-MRI, and suggest that stromal enhancement measurements may be worth exploring as a potential predictor of recurrence/disease-free survival following NACT. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-01-04.