The effect of breast MRI on disease-free and overall survival in breast cancer patients: a retrospective population-based study

Purpose: To evaluate the effect of breast MRI on overall survival (OS) and disease-free survival (DFS) of patients with invasive breast cancer in the Netherlands. Methods: We selected all women from the Netherlands Cancer Registry diagnosed with invasive breast cancer (a) between 2011 and 2013 for the OS-cohort and (b) in the first quarter of 2012 for the DFS-cohort. The study population was subdivided into an MRI and non-MRI group. In addition, subgroups were created according to breast cancer subtype: invasive carcinoma of no special type (NST) versus invasive lobular carcinoma (ILC). OS and DFS were compared between the MRI and non-MRI group using the Kaplan–Meier method and the log-rank test. Cox proportional hazard regression analysis was performed to estimate hazard ratios (HR) with a 95% confidence interval (CI). To account for missing data, multiple imputation was performed. Results: Of the 31,756 patients included in the OS-cohort (70% non-MRI and 30% MRI), 27,752 (87%) were diagnosed with invasive carcinoma NST and 4004 (13%) with ILC. Of the 2464 patients included in the DFS-cohort (72% non-MRI and 28% MRI), 2161 (88%) were diagnosed with invasive carcinoma NST and 303 (12%) with ILC. The distribution of breast MRI use was significantly lower over different age categories, from 49.0% aged < 50 to 16.5% aged > 70. Multivariable Cox regression showed that breast MRI was not significantly associated with OS overall (HR 0.91, 95%-CI 0.74–1.11, p = 0.35), nor in the different histological subtypes. Multivariable Cox regression analysis showed that breast MRI was also not significantly associated with DFS (HR 1.16, 95%-CI 0.81–1.67), nor in the different histological subtypes. Conclusion: Use of breast MRI was not significantly associated with an improved OS or DFS in patients treated with primary surgery.