Abstract P2-02-10: Clinical Utility of MRI before Re-Lumpectomy in Breast Conserving Operation

Abstract

Abstract Background: It was necessary to know the resection margin status for breast conserving operations after diagnostic excisional biopsies. The purposes of this study were to assess the accuracy of breast MRI in detecting residual tumor extent around excisional biopsy or mammotome biopsy sites with unknown resection margin status and evaluate the impact of MRI on surgical treatment planning for breast conserving operation. Material and Methods: Preoperative breast MRI was performed in 47 breast cancer patients who underwent mammotome biopsy and excisional biopsy with unknown resection margin status. All subjects underwent breast MRI and ultrasonography for extent of residual tumor, and were evaluated by experienced two diagnostic radiologists, followed by immediate curative operation. We investigated the correlation between radiologic and pathologic finding and the radiologic decision's effect on further surgical treatment. Results: 28 patients(59.6%) were taken by excisional biopsy, 13 patients by mammotome biopsy(27.7%), and 6 patients(12.8%) by lumpectomy. Twenty-five patients (53.1%) underwent re-lumpectomy, while 19 patients (40.4%) mastectomy, and 3 patients(6.3%) only sentinel lymph node biopsy. Residual tumor was present in 33 patients (70.3%) and multifocal breast cancer was found in 12 patients (25.5%). In terms of the accuracy of MRI in detecting residual tumor, the sensitivity was 63.6%, specificity was 45.5% and the positive predictive value was 77.7%. In that of ultrasonographies, the sensitivity was 52.3%, specificity was 88.8%, and the positive predictive value was 91.6%. Pathologic finding of residual tumor showed that ductal carcinoma in situ was most common (57.1%) in not only radiologic-pathologic concordant cases, but also in radioloigc-pathologic discordant cases (58.3%). But 5 patients (10.6%) with invasive ductal carcinoma in residual tumor were not detected by MRI. Positive predictive value was not associated with residual tumor sizes. The MR findings of residual tumor changed the next procedure from re-lumpectomy to mastectomy (10 patients), additional biopsy of suspicious lesion in ipsilateral breast (2 patients), and second-look ultrasonography (4 patients). Discussion: Preoperative MRI was not critical effect on evaluating the margin status around excisional biopsy sites. An important clinical role of MRI is to identify a subset of patients with extensive residual or multifocal breast cancer who would be better served by undergoing mastectomy rather than breast conserving operation. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-02-10.