Does preoperative MRI influence the extent of surgical resection in conservative breast cancer surgery?

We assessed prospectively the impact of preoperative breast magnetic resonance (MRI) on the extent of surgical resection. Of 131 breast cancers treated with breast conservation over 18 months, 41 underwent preoperative MRI. Scans were shown to the operating surgeon to indicate the location of lesions and their local extent. Clinical information and histological assessment of wide local excision specimens were compared between those patients who underwent preoperative MRI and those who did not. There was no significant difference between the MRI group (n=41) and no-MRI group (n=90) in average specimen weight (P = 0.72) or circumferential margin status (P = 0.17). Logistic regression analysis demonstrated a positive correlation between margin status and patient age (P = 0.045), younger patients being more likely to have involved margins, and a negative correlation with MRI status (P = 0.006) these women having an MRI being more likely to have negative margins. Preoperative MRI does not currently influence the extent of surgical resection in breast conservation surgery.