Association between rim enhancement of breast cancer on dynamic contrast-enhanced MRI and patient outcome: impact of subtype.

The heterogeneous nature of breast cancer is represented by three breast cancer subtypes associated with different patient outcome. However, within subtypes, variations still exist. Additional stratification is necessary for more individualized therapy. Functional tumor characteristics on dynamic contrast-enhanced (DCE)-MRI may play a role. Rim enhancement of breast cancers has been associated with unfavorable pathology characteristics in the context of outcome. However, existence of a direct link is unknown. The purpose was to retrospectively determine the association between rim enhancement on DCE-MRI and long-term patient outcome, and whether it has complementary value to subtype. Preoperative DCE-MRI was performed in 556 consecutive female patients who were eligible for breast-conserving therapy. Presence of rim enhancement was assessed. Tumor characteristics were derived from resection specimens. Patients were stratified according to subtype. Association was assessed between rim enhancement and patient, pathology and treatment characteristics, recurrence-free interval and invasive disease-free survival. Median follow-up was 84 months. Patients were stratified into ER-positive/HER2-negative (N = 416), HER2-positive (N = 75), or triple-negative (N = 65) subtypes. Rim enhancement was seen in 29.0% (N = 161/556) of tumors and was associated with higher histologic grade, negative ER-status, and triple-negative subtype. Only within triple-negative tumors, an association was seen with outcome. Recurrence was lower in non-rim-enhancing tumors (N = 1/36; 2.8%) compared to rim-enhancing tumors (N = 9/28; 32.1%) (p = 0.001). Survival was higher in non-rim-enhancing tumors (N = 34/36; 94.4%) compared to rim-enhancing tumors (N = 18/28; 64.3%) (p = 0.001). Rim enhancement on DCE-MRI is associated with long-term outcome of patients with triple-negative breast cancer and may potentially serve as a prognostic biomarker in these patients.