Can enhancement types on preoperative MRI reflect prognostic factors and surgical outcomes in invasive breast cancer?

Objectives: This study was conducted in order to evaluate whether enhancement types on preoperative MRI can reflect prognostic factors and surgical outcomes in invasive breast cancer.

Methods: Among 484 consecutive patients who underwent preoperative breast MRI from October 2014 to July 2017 for biopsy-proven breast cancer, 313 patients with 315 invasive breast cancers who underwent subsequent surgery were finally included in this study. Two radiologists retrospectively reviewed preoperative MRI findings of these 315 lesions and categorized them to mass, nonmass, and combined type according to enhancement features. Combined type was defined as coexisted mass and nonmass enhancement. Histopathologic results focusing on prognostic factors and surgical outcomes were compared among the three types of lesion using Pearson's chi-square, linear-by-linear association, Kruskal-Wallis, one-way ANOVA test, and multinomial logistic regression.

Results: Of the cancers analyzed, 198 (62.9%) were mass, 59 (18.7%) were nonmass, and 58 (18.4%) were combined type. The nonmass type showed the smallest invasive tumor size (p < 0.001) and the most common positive HER2 receptor status (p = 0.001). The combined type had the most frequent lymphovascular invasion (p = 0.011), axillary lymph node-positive status (p = 0.031), operation changes (p < 0.001), and first resection margin-positive status (p < 0.001). Initial operation of mastectomy was more frequent in the nonmass and combined types than that in the mass type (p < 0.001). But HER2 receptor status and operation changes showed no statistical significance on multivariate analysis.

Conclusions: Enhancement types on preoperative MRI reflect different prognostic factors and surgical outcomes in invasive breast cancer.

Key Points: • Morphologic features of contrast media uptake on contrast-enhanced MRI may be related with fundamental biological differences of invasive breast cancers. • Mass or nonmass enhancement type on preoperative MRI might reflect different prognostic factors and surgical outcomes in invasive breast cancer. • The combined mass and nonmass enhancement type might be associated with poorer prognosis and worse surgical outcomes.