The efficacy of breast MRI in predicting breast conservation therapy

Background: Breast conservation therapy (BCT) has equal efficacy compared to mastectomy in treating breast cancer. Accurate pre-operative measurement of tumor size can limit re-excision procedures. Breast MRI may improve pre-operative evaluation of extent of disease. Objective: To examine the correlation of extent of disease on breast MRI with pathologic data to determine the utility of breast MRI in surgical planning of BCT. Methods: We retrospectively reviewed our prospective database of women undergoing breast MRI. We identified 115 women with breast cancer who underwent a breast MRI and a surgical resection from 2000 to 2003. We compared patients with high-grade tumors (HG, n = 40) to patients with low grade (LG, n = 75). Results: The size of the tumor on MRI correlated with the pathologic size for HG tumors (HG R = 0.76 vs. LG R = 0.45, P = 0.033). Mastectomy was performed in 53 patients. In 10 patients with LG tumors, the MRI findings overestimated their disease. In 11 out of 115 patients the primary tumor or a second tumor was only seen by MRI. Conclusion: Breast MRI does change surgical management by detecting additional malignancies. Breast MRI is accurate in staging extent of disease in the breast in patients with HG tumors.