Correlation of tumor size on preoperative breast MRI and pathologic tumor size in Asian patients

e11546 Background: As many Asian patients want breast conserving therapy (BCT), use of magnetic resonance imaging (MRI) increase in preoperative diagnosis for breast cancer. But the impact of MRI on these patients has not been unclear. Methods: From January 2008 to July 2008, 423 patients underwent breast cancer surgery in National Cancer Center, Korea. We enrolled 357 patients consecutively in this retrospective study; 290 patients (non-MRI group) with preoperative mammography (MMG) and ultrasonography (US) vs. 66 patients (MRI group) with additional MRI to MMG, US and excluded 67 patients (42 patients with preoperative chemotherapy, 8 patients with ipsilateral recurrence, 17 patients whose MRI showed no residual lesion after excisional biopsy). We examined MRI effect on mastectomy rate, intraoperative conversion from BCT to mastectomy, positive margin rate in frozen specimen in both group. In MRI group, we evaluated the correlation between tumor size on US, MRI and pathologic tumor size. Results: Mean a...