title: The impact of preoperative MRI on breast-conserving surgery of invasive cancer: a comparative cohort study.
abstract: OBJECTIVE
  To assess whether preoperative contrast-enhanced magnetic resonance imaging (MRI) of the breast influences the rate of incomplete tumor excision.
  
  
  METHODS
  In a cohort of 349 women with invasive breast cancer, patients eligible for breast-conserving therapy (BCT) on the basis of conventional imaging and palpation only (N = 176) were compared to those who had an additional preoperative MRI (N = 173). Multivariate analysis was applied to explore associations with incomplete tumor excision.
  
  
  RESULTS
  MRI detected larger extent of breast cancer in 19 women (11.0%), leading to treatment change: mastectomy (8.7%) or wider excision (2.3%). Tumor excision was incomplete in 22/159 (13.8%) wide local excisions in the MRI group and in 35/180 (19.4%) in the non-MRI group (P = 0.17). Stratified to tumor type, incompletely excised infiltrating ductal carcinoma (IDC) was significantly associated with absence of MRI: 11/136 (8.1%) versus 2/126 (1.6%) (MRI present) (P = 0.02). No significant factors explained incomplete excision of other tumor types.
  
  
  CONCLUSIONS
  Preoperative MRI did not significantly affect the overall rate of incomplete tumor excision, but it yielded significantly lower rate of incompletely excised IDC. The reduction of incomplete excisions after MRI was smaller than the rate of a prior treatment change incurred by MRI.
authors.affiliation: Department of Radiology, The Netherlands Cancer Institute, Antoni van Leeuwenhoek Hospital (NKI-AVL), Amsterdam, The Netherlands.
authors.forename: K E
authors.initials: KE
authors.lastname: Pengel
authors.forename: C E
authors.initials: CE
authors.lastname: Loo
authors.forename: H J
authors.initials: HJ
authors.lastname: Teertstra
authors.forename: S H
authors.initials: SH
authors.lastname: Muller
authors.forename: J
authors.initials: J
authors.lastname: Wesseling
authors.forename: J L
authors.initials: JL
authors.lastname: Peterse
authors.forename: H
authors.initials: H
authors.lastname: Bartelink
authors.forename: E J
authors.initials: EJ
authors.lastname: Rutgers
authors.forename: K G A
authors.initials: KG
authors.lastname: Gilhuijs
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000473:pathology* / Q000601:surgery*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D015412:Mastectomy, Segmental; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods*; D016896:Treatment Outcome