MRI for Surgical Planning in Patients with Breast Cancer Who Undergo Preoperative Chemotherapy

Accurate presurgical evaluation of residual disease appears essential for successful clinical outcome in patients with breast cancer who are undergoing chemotherapy. Our objective was to study the impact on surgical planning of adding serial MRI evaluations of the tumor to standard non-MRI assessments.MR images of breast tumors obtained before, during, and after preoperative chemotherapy were reviewed in 30 patients. Tumor response was assessed using both size and morphologic MRI criteria. We compared the actual surgical decisions made prospectively on the basis of standard (clinical, mammographic, and sonographic) assessments of response with decisions that would have been made had MRI findings also been considered. MRI investigators were blinded to the ultimate surgical results. Successful breast-conserving surgery was judged on pathologic confirmation of excision margins that were negative for cancer.The standard evaluation led to 16 successful breast-conserving and 14 mastectomy procedures. Using MRI results would have led to major beneficial therapeutic changes in six (20%) of the 30 patients: five patients undergoing primary mastectomy (chemotherapy avoided) and one patient undergoing postchemotherapy mastectomy (unsuccessful breast-conserving surgery avoided). MRI would have added valuable information in 14 (46.7%) of the 30 patients. In seven (23.3%) of the 30 patients, the decision to perform postchemotherapy mastectomy would have been unchanged. In one patient (3.3%), MRI results would not have prevented unsuccessful breast-conserving surgery. In two patients (6.6%), MRI results would have prevented successful breast-conserving surgery from being performed.Although the ultimate incidence of breast conservation was potentially similar for the patients (16/30, 53%) in whom the standard evaluation was used and for the patients (14/30, 47%) in whom the MRI-added evaluation was used, MRI was useful in establishing the final treatment earlier in the process, avoiding unnecessary preoperative chemotherapy, or selecting high-risk breast-conserving procedures.