title: Preoperative MRI and surgical management in patients with nonpalpable breast cancer: the MONET - randomised controlled trial.
abstract: BACKGROUND
  We evaluated whether performing contrast-enhanced breast MRI in addition to mammography and/or ultrasound in patients with nonpalpable suspicious breast lesions improves breast cancer management.
  
  
  METHODS
  The MONET - study (MR mammography of nonpalpable breast tumours) is a randomised controlled trial in patients with a nonpalpable BIRADS 3-5 lesion. Patients were randomly assigned to receive routine medical care, including mammography, ultrasound and lesion sampling by large core needle biopsy or additional MRI preceding biopsy. Patients with cancer were referred for surgery. Primary end-point was the rate of additional surgical procedures (re-excisions and conversion to mastectomy) in patients with a nonpalpable breast cancer.
  
  
  RESULTS
  Four hundred and eighteen patients were randomised, 207 patients were allocated to MRI, and 211 patients to the control group. In the MRI group 74 patients had 83 malignant lesions, compared to 75 patients with 80 malignant lesions in the control group. The primary breast conserving surgery (BCS) rate was similar in both groups; 68% in the MRI group versus 66% in the control group. The number of re-excisions performed because of positive resection margins after primary BCS was increased in the MRI group; 18/53 (34%) patients in the MRI group versus 6/50 (12%) in the control group (p=0.008). The number of conversions to mastectomy did not differ significantly between groups. Overall, the rate of an additional surgical intervention (BCS and mastectomy combined) after initial breast conserving surgery was 24/53 (45%) in the MRI group versus 14/50 (28%) in the control group (p=0.069).
  
  
  CONCLUSIONS
  Addition of MRI to routine clinical care in patients with nonpalpable breast cancer was paradoxically associated with an increased re-excision rate. Breast MRI should not be used routinely for preoperative work-up of patients with nonpalpable breast cancer.
authors.affiliation: Dept. of Radiology, University Medical Center Utrecht, The Netherlands.
authors.forename: N H G M
authors.initials: NH
authors.lastname: Peters
authors.forename: S
authors.initials: S
authors.lastname: van Esser
authors.forename: M A A J
authors.initials: MA
authors.lastname: van den Bosch
authors.forename: R K
authors.initials: RK
authors.lastname: Storm
authors.forename: P W
authors.initials: PW
authors.lastname: Plaisier
authors.forename: T
authors.initials: T
authors.lastname: van Dalen
authors.forename: S C E
authors.initials: SC
authors.lastname: Diepstraten
authors.forename: T
authors.initials: T
authors.lastname: Weits
authors.forename: P J
authors.initials: PJ
authors.lastname: Westenend
authors.forename: G
authors.initials: G
authors.lastname: Stapper
authors.forename: M A
authors.initials: MA
authors.lastname: Fernandez-Gallardo
authors.forename: I H M
authors.initials: IH
authors.lastname: Borel Rinkes
authors.forename: R
authors.initials: R
authors.lastname: van Hillegersberg
authors.forename: W P Th M
authors.initials: WP
authors.lastname: Mali
authors.forename: P H M
authors.initials: PH
authors.lastname: Peeters
mesh_terms: D001707:Biopsy, Needle / Q000379:methods; D001943:Breast Neoplasms / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008327:Mammography / Q000379:methods; D008408:Mastectomy / Q000706:statistics & numerical data; D015412:Mastectomy, Segmental / Q000379:methods*; D008875:Middle Aged; D011300:Preoperative Care; D012086:Reoperation / Q000706:statistics & numerical data