Preoperative staging with magnetic resonance imaging, with confirmatory biopsy, improves surgical outcomes in women with breast cancer without increasing rates of mastectomy.

Needle biopsy to evaluate findings on MRI that could alter surgical planning has been recommended. This study is a retrospective review to evaluate MRI preoperative staging with biopsy confirmation of suspicious findings. A total of 184 women were diagnosed with breast cancer between January 2004 and June 2008. Of these, 79 underwent bilateral MRI before definitive surgery and 105 did not. Suspicious findings on MRI, mammography, or clinical exam underwent additional needle biopsy at the discretion of the surgeon. A retrospective chart review was performed to compare the two groups with respect to rates of reoperative surgery, successful breast conservation, and confirmatory biopsies. Sensitivity and specificity of MRI for preoperative staging is 0.81 and 0.84, respectively. There were no significant differences in demographics or cancer characteristics between the MRI and non-MRI groups. Fewer women who underwent preoperative MRI staging required repeat breast surgery (11% versus 26%, p = .04) or repeat axillary surgery (10% versus 20%, p = .05). There is no difference in the proportion of women who successfully completed conservative therapy and those treated radically (52% versus 53%), but there is a significant increase in women who undergo additional needle biopsy to confirm suspicious findings after initial diagnosis in the MRI group (25% versus 11% p = .04). In this study, mastectomy rates are not increased; suggesting that women who undergo mastectomy following staging would undergo mastectomy following failed conservative therapy if they were not staged. The downside of this improvement is a 14% increase in women who require confirmatory biopsy.