title: Does background parenchymal enhancement on MRI affect the rate of positive resection margin in breast cancer patients?
abstract: OBJECTIVE
  The purpose of our study was to evaluate whether strong background parenchymal enhancement (BPE) would be a significant independent factor associated with positive resection margin in patients treated initially with breast-conserving surgery (BCS).
  
  
  METHODS
  Retrospective evaluation of breast MRI examinations of 314 patients with breast cancer was carried out. Breast cancer was histologically confirmed in all patients who underwent BCS from January 2008 to December 2010. BPE was dichotomized into weak (minimal or mild) and strong (moderate or marked) enhancement for statistical analysis. Histopathological features of attained specimens were evaluated by an experienced pathologist and were also dichotomized for statistical analysis.
  
  
  RESULTS
  On univariate analysis, positive extensive intraductal component (p < 0.001), strong BPE (p = 0.001) and human epidermal growth factor receptor 2 (HER2) positivity (p = 0.08) had significant association with positive surgical margin. Tumour size, axillary lymph node metastasis, nuclear grade, histological grade, lymphovascular invasion, oestrogen receptor and progesterone receptor did not show significant correlation with positive surgical margin. On multivariate analysis, the significant independent predictors were extensive intraductal component [odds ratio, 5.68; 95% confidence interval (CI), 2.72-11.82] and strong BPE (odds ratio, 2.39; 95% CI, 1.20-4.78).
  
  
  CONCLUSIONS
  Strong BPE is a significant independent factor for positive resection margin along with positive extensive intraductal component, and performing MRI during the period of lower parenchymal enhancement is needed in patients with strong BPE.
  
  
  CONCLUSIONS
  As far as we know, this is the first study to reveal that BPE is a significant independent factor associated with positive resection margin.
authors.affiliation: Department of Radiology, Ajou University School of Medicine, Suwon, Republic of Korea.
authors.forename: S Y
authors.initials: SY
authors.lastname: Park
authors.forename: D K
authors.initials: DK
authors.lastname: Kang
authors.forename: T H
authors.initials: TH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015412:Mastectomy, Segmental; D008875:Middle Aged; D012189:Retrospective Studies