P2-08-13: Does Routine Use of Preoperative Magnetic Resonance Imaging (MRI) in Breast Cancer Influence the Outcome?

Introduction: The role of routine preoperative breast MRI in patients diagnosed with breast cancer is still under discussion. In a milestone review, Houssami et al. (CA Cancer J Clin 2009;59;290) did not demonstrate an advantage with regard to DFS or OS. We reviewed our case series (n=793) in order to add evidence to the current discussion of whether or not preoperative MRI would influence the outcome. Material and Methods: In our database we identified four years of diagnosis (2004-07) in which a high percentage (72%) of patients (349 of 483) with histologically confirmed invasive breast cancer received preoperative MRI. In the following years (2008/09), MRI was still done in 31% of the cases (97 of 309). All pts were treated according to national guidelines; however, patients with additional lesions in MRI were subjected to an additional MRI-guided needle biopsy or additional wire-guided excision. The median follow-up time was 31.5 months (0-81). The patients were followed clinically. In most cases local surveillance was done by mammography. Results: In the total cohort, 20% of the patients had additional needle biopsies and/or wire-localisation due to MRI-findings. By MRI, lesions that subsequently led to an additional preoperative needle biopsy were found in 82 pts. Interestingly, only ten contralateral second cancers were found. In 357 pts, MRI was used as guidance during the operation with (n=118) or without MRI-supported wire localization (n=238). The percentage of additional MRI-needle biopsy or MRI-supported localisation did not differ between invasive ductal (n=655) and lobular cancer (n=91): 10% versus 13% needle biopsies and 15% versus 20% wire localisations. The number of surgical procedures to achieve tumor-free margins did not differ between patients with or without preoperative MRI. In this series, 69 of 100 patients who received neoadjuvant chemotherapy, also had MRI-imaging. Considering the patient cohort with follow-up available (n=737), no significant difference of DFS probability was observed between pts with and without preoperative MRI. Discussion: This retrospective analysis did not demonstrate any advantage for routine preoperative MRI with regard to local treatment and DFS probability. The observed rate of 20% additional operative procedures corresponds to similar published data (16% additional multicentric or multifocal lesions found by MRI, Solin, Breast. 2010;19:7). Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-08-13.