Prognostic Value of MRI Assessment of Residual Peritumoral Edema in Breast Cancer Treated With Neoadjuvant Chemotherapy.

Background: Peritumoral edema (PE) identified on T2-weighted breast MRI is a factor for poor prognosis in breast cancer.

Purpose: To assess the prognostic value of residual PE (rPE) in patients with PE positive breast cancer prior to neoadjuvant chemotherapy (NACT) who subsequently underwent curative surgery.

Study Type: Retrospective.

Population: In total, 128 patients with nonmetastatic invasive breast cancer who underwent breast MRI before and after NACT.

Field Strength/sequence: Axial precontrast 2D fast spin echo T2W fat-suppressed sequence. Axial dynamic 3D gradient echo T1W fat-suppressed sequence.

Assessment: PE was diagnosed when a signal intensity as high as water was detected surrounding the tumor on a T2-weighted breast MRI. PE was qualitatively evaluated by three readers with more than 20 years of experience in interpreting breast field imaging findings. Residual cancer burden (RCB) were assessed post-NACT. Recurrence-free survival (RFS) and overall survival (OS) were evaluated as the endpoints of this study.

Statistical Tests: Chi-square test; Kaplan-Meier method, log-rank test, and Cox proportional hazard model. A P-value <0.05 was considered statistically significant.

Results: Pre-PE was observed in 64 out of 128 patients. Of these, rPE was observed in 21. In the log-rank test, breast cancer with rPE had significantly worse RFS and OS than that without rPE. Cox proportional hazard analysis identified rPE as a significant prognostic factor for recurrence (hazard ratio, 11.6; 95% confidence interval [CI], 3.05-43.8) and death (hazard ratio, 17.8; 95% CI, 3.30-96.3). Breast cancer with rPE had significant worse RFS and OS than that without rPE in RCB class II, and significant worse OS in pathological complete response, class I and class II in the log-rank test.

Data Conclusion: rPE on a T2-weighted breast MRI was a significant factor for breast cancer recurrence and death in patients with pre-PE-positive breast cancer treated with NACT.

Technical Efficacy: Stage 2.