Long-term survival outcomes in invasive lobular carcinoma patients with and without preoperative MR imaging: a matched cohort study.

<bold>Objective: </bold>To investigate and compare the effect of preoperative breast magnetic resonance (MR) imaging on recurrence-free survival (RFS) and overall survival (OS) outcomes among patients with invasive lobular carcinoma (ILC).<bold>Methods: </bold>A total of 287 ILC patients between January 2005 and December 2012 were included. One hundred twenty (41.8%) had undergone preoperative breast MR imaging (MR group) and 167 (58.2%) had not (no MR group). Two groups were matched for 21 covariates in terms of patient demographics, tumor characteristics, and clinical features. We compared unmatched variables between the patients with and without breast MR imaging using the chi-square or Student's t test. Comparisons of matched data were performed with McNemar's test or test of symmetry for categorical variables and paired t test for continuous variables. The RFS and OS outcomes were compared using the Kaplan-Meier estimates. MR effects were estimated after adjusting for significant potential confounders of specific outcomes in the multivariable modeling.<bold>Results: </bold>In the matched cohort, no statistically significant association was observed between MR imaging and total recurrence (hazard ratio [HR], 1.096; p = 0.821), loco-regional recurrence (HR, 1.204; p = 0.796), contralateral breast recurrence (HR, 0.945; p = 0.952), or distant recurrence (HR, 1.020; p = 0.973). MR imaging was associated with improved OS with 51% reduction, but not significantly (HR, 0.485; p = 0.231). Analysis with multivariable Cox regression model indicated that MR imaging was not significant independent factor for better RFS (HR, 0.823; p = 0.586) or improved OS (HR, 0.478; p = 0.168).<bold>Conclusion: </bold>Preoperative MR imaging is not significant prognostic factor and produces no apparent recurrence or survival outcome benefits in ILC patients.<bold>Key Points: </bold>• Preoperative breast MR imaging in invasive lobular carcinoma was associated with a better overall survival with 51% reduction, but not statistically significant. • Preoperative breast MR imaging does not show significant prognostic value in invasive lobular carcinoma as there is no apparent benefit in terms of recurrence or survival outcomes. [ABSTRACT FROM AUTHOR]