title: Use of Preoperative Magnetic Resonance Imaging for Breast Cancer: A Canadian Population-Based Study.
abstract: OBJECTIVE
  Contrary to practice guidelines, breast magnetic resonance imaging (MRI) is commonly used in the preoperative evaluation of women with breast cancer. While existing literature has found little benefit to MRI in most patients, potential downstream consequences associated with breast MRI are not well described.
  
  
  OBJECTIVE
  To describe patterns of preoperative breast MRI utilization in a health care system with universal insurance and its association with downstream investigations and clinical outcomes.
  
  
  METHODS
  This was a population-based retrospective cohort study using administrative heath care databases in Ontario, Canada (2012 population, 13.5 million) over 14 geographic regions were evaluated within the data set. Participants comprised 53 015 patients with primary operable breast cancer treated from 2003 to 2012.
  
  
  METHODS
  Use of preoperative breast MRI by year, geographic region, and breast cancer stage. Postdiagnosis imaging, biopsy, and short-term surgical outcomes were also evaluated between those who did and did not receive MRI.
  
  
  RESULTS
  Overall, 14.8% of patients (7824 of 53 015) had a preoperative MRI. During the 10-year study period, MRI use increased across all stages by 8-fold (from 3% to 24%; P < .001 for trend). Factors associated with MRI use were younger age, higher socioeconomic status, higher Charlson comorbidity score, surgery performed in a teaching hospital, and fewer years of surgeon experience. Multivariate analyses showed that preoperative breast MRI was associated with higher likelihood of the following: postdiagnosis breast imaging (odds ratio [OR], 2.09; 95% CI, 1.92-2.28), postdiagnosis breast biopsies (OR, 1.74; 95% CI, 1.57-1.93), postdiagnosis imaging to assess for distant metastatic disease (OR, 1.51; 95% CI, 1.42-1.61), mastectomy (OR, 1.73; 95% CI, 1.62-1.85), contralateral prophylactic mastectomy (OR, 1.48; 95% CI, 1.23-1.77), and a greater than 30-day wait to surgery (OR, 2.52; 95% CI, 2.36-2.70) (all ORs are adjusted).
  
  
  CONCLUSIONS
  Preoperative breast MRI use has increased substantially in routine clinical practice and is associated with a significant increase in ancillary investigations, wait time to surgery, mastectomies, and contralateral prophylactic mastectomies.
authors.affiliation: Division of General Surgery, Ottawa Hospital, Ottawa, Ontario, Canada2Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Angel
authors.initials: A
authors.lastname: Arnaout
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Catley
authors.affiliation: Division of Cancer Care and Epidemiology, Queens University Cancer Research Institute, Kingston, Ontario, Canada4Department of Oncology, Queens University, Kingston, Ontario, Canada.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Booth
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada5Department of Radiology, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Matthew
authors.initials: M
authors.lastname: McInnes
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada6School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Ian
authors.initials: I
authors.lastname: Graham
authors.affiliation: Department of Oncology, Queens University, Kingston, Ontario, Canada.
authors.forename: Vikaash
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Department of Medical Oncology, Ottawa Hospital Cancer Center, Ottawa, Ontario, Canada.
authors.forename: Demetrios
authors.initials: D
authors.lastname: Simos
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada.
authors.forename: Carl
authors.initials: C
authors.lastname: Van Walraven
authors.affiliation: Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada7Department of Medical Oncology, Ottawa Hospital Cancer Center, Ottawa, Ontario, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Clemons
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data / Q000639:trends; D008408:Mastectomy / Q000706:statistics & numerical data; D008875:Middle Aged; D009864:Ontario; D011300:Preoperative Care / Q000379:methods; D012189:Retrospective Studies; D061665:Time-to-Treatment / Q000706:statistics & numerical data; D016896:Treatment Outcome