title: Breast MRI increases the number of mastectomies for ductal cancers, but decreases them for lobular cancers.
abstract: In this retrospective population-based cohort study, we analyzed breast MRI use and its impact on type of surgery, surgical margin involvement, and the diagnosis of contralateral breast cancer.
  
  
  
  All Dutch patients with cT1-4N0-3M0breast cancer diagnosed in 2011-2013 and treated with primary surgery were eligible for inclusion. Using multivariable analyses, we analyzed in different categories whether MRI use was related to surgery type, margin involvement, and diagnosis of contralateral breast cancer (CBC).
  
  
  
  MRI was performed in 10,740 out of 36,050 patients (29.8%). Patients with invasive ductal cancer undergoing MRI were more likely to undergo primary mastectomy than those without MRI (OR 1.30, 95% confidence interval (CI) 1.22-1.39, p < 0.0001). Patients with invasive lobular cancer undergoing MRI were less likely to undergo primary mastectomy than those without MRI (OR 0.86, 95% CI 0.76-0.99, p = 0.0303). A significantly lower risk of positive surgical margins after breast-conserving surgery was only seen in patients with lobular cancer who had undergone MRI as compared to those without MRI (OR 0.59, 95% CI 0.44-0.79, p = 0.0003) and, consequently, a lower risk of secondary mastectomy (OR 0.61, 95% CI 0.42-0.88, p = 0.0088). Patients who underwent MRI were almost four times more likely to be diagnosed with CBC (OR 3.55, 95% CI 3.01-4.17, p < 0.0001).
  
  
  
  Breast MRI use was associated with a reduced number of mastectomies and less positive surgical margins in invasive lobular cancer, but with an increased number of mastectomies in ductal cancers. Breast MRI use was associated with a fourfold higher incidence of CBC.
authors.affiliation: Maastricht University Medical Center, Department of Radiology and Nuclear Medicine, 5800, 6202 AZ, Maastricht, The Netherlands. marc.lobbes@mumc.nl.
authors.forename: Marc B I
authors.identifier: 0000-0002-2103-6956
authors.initials: MB
authors.lastname: Lobbes
authors.affiliation: Maastricht University Medical Center, Department of Medical Oncology, Maastricht, The Netherlands.
authors.forename: Ingeborg J H
authors.initials: IJ
authors.lastname: Vriens
authors.affiliation: Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Annelotte C M
authors.initials: AC
authors.lastname: van Bommel
authors.affiliation: Catharina Hospital, Department of Surgery, Eindhoven, The Netherlands.
authors.forename: Grard A P
authors.initials: GA
authors.lastname: Nieuwenhuijzen
authors.affiliation: Maastricht University Medical Center, Department of Surgery, Maastricht, The Netherlands.|Maastricht University, Department of Epidemiology, Maastricht, The Netherlands.
authors.forename: Marjolein L
authors.initials: ML
authors.lastname: Smidt
authors.affiliation: Maastricht University Medical Center, Department of Radiation Oncology (MAASTRO Clinic), Maastricht, The Netherlands.
authors.forename: Liesbeth J
authors.initials: LJ
authors.lastname: Boersma
authors.affiliation: Diakonessenhuis Utrecht, Utrecht, The Netherlands.
authors.forename: Thijs
authors.initials: T
authors.lastname: van Dalen
authors.affiliation: Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
authors.forename: Carolien
authors.initials: C
authors.lastname: Smorenburg
authors.affiliation: Medical Center Haaglanden, The Hague, The Netherlands.
authors.forename: Henk
authors.initials: H
authors.lastname: Struikmans
authors.affiliation: Comprehensive Cancer Organisation the Netherlands, Utrecht, The Netherlands.|MIRA Institute of Biomedical Technology and Technical Medicine, Department of Health Technology and Services Research, University of Twente, Enschede, The Netherlands.
authors.forename: Sabine
authors.initials: S
authors.lastname: Siesling
authors.affiliation: Maastricht University Medical Center, Department of Medical Oncology, Maastricht, The Netherlands.|Comprehensive Cancer Organisation the Netherlands, Utrecht, The Netherlands.|Maastricht University, Department of Epidemiology, Maastricht, The Netherlands.
authors.forename: Adri C
authors.initials: AC
authors.lastname: Voogd
authors.affiliation: Maastricht University Medical Center, Department of Medical Oncology, Maastricht, The Netherlands.|GROW School for Oncology and Developmental Biology, Maastricht, The Netherlands.
authors.forename: Vivianne C G
authors.initials: VC
authors.lastname: Tjan-Heijnen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D018270:Carcinoma, Ductal, Breast / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D008408:Mastectomy / Q000379:methods / Q000706:statistics & numerical data; D008875:Middle Aged; D060787:Neoplasm Grading; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D009426:Netherlands / Q000453:epidemiology; D011159:Population Surveillance; D012189:Retrospective Studies
keywords: Breast cancer; Contralateral breast cancer; Lobular cancer; MRI; Surgery