The impact of breast MRI on surgical decision-making: Are patients at risk for mastectomy?

Background and Objectives: The goal of the current study was to determine whether MRI impacts multidisciplinary treatment planning and if it leads to increased mastectomy rates. Methods: A retrospective review was conducted of 441 patients treated for breast cancer between January 2005 and May 2008 who underwent breast MRI. Data included number of additional findings and their imaging and pathologic work-up. This was analyzed to determine impact of MRI on treatment planning. Results: Of 441 patients, 45% had ≥1 additional finding on MRI. Of 410 patients with complete records, 29% had changes in the treatment plan, including 36 patients who were initially considered for breast conservation but proceeded directly to mastectomy based on MRI findings of suspected multicentricity. Twenty-three of those patients did not have a biopsy of the MRI lesion, with 87% having unicentric disease on final pathology. Overall, the mastectomy rate was 44%, which was significantly increased compared to patients not undergoing MRI (32%, P<0.05). Conclusions: Breast MRI alters the treatment planning for many patients with newly diagnosed breast cancer. Mastectomy rates are increased when MRI results alone direct surgical planning. Biopsy of MRI-identified lesions should be performed to avoid over-treatment.