Breast parenchymal signal enhancement ratio at preoperative magnetic resonance imaging: Association with early recurrence in triple-negative breast cancer patients

Background: The signal enhancement ratio (SER) of surrounding non-tumor parenchyma at breast magnetic resonance imaging (MRI) can be helpful in breast cancer patients, but has not been investigated in patients with triple negative breast cancer (TNBC). Purpose: To investigate the association between background parenchymal SER around the tumor on preoperative dynamic contrast-enhanced MRI with recurrence-free survival in patients with TNBC. Material and Methods: Between April 2012 and May 2013, 71 TNBC patients who underwent preoperative MRI were included. SER values were calculated from regions of interest placed in the breast parenchyma around the tumor. Cox proportional hazards models were used to determine associations between MRI variables, clinical-pathologic variables, and recurrence-free survival. Results: Recurrence occurred in 8.5% (6/71) of patients. At univariate analysis, a higher SER around the tumor, larger tumor size, lymphovascular invasion, lymph node metastasis, receipt of neoadjuvant chemotherapy, receipt of total mastectomy, and not receiving adjuvant chemotherapy were associated with worse recurrence-free survival. At multivariate analysis of preoperative variables, a higher SER around the tumor was independently associated with worse recurrence-free survival (hazard ratio [HR]7.072, P0.003 for SER1; HR6.268, P0.006 for SER2; HR3.004, P0.039 for SER3). Conclusion: Higher SER around the tumor at preoperative dynamic contrast-enhanced MRI is an independent predictor for recurrence in TNBC patients.