Use of MRI in preoperative planning for women with newly diagnosed DCIS: risk or benefit?

Abstract

The role of magnetic resonance imaging (MRI) in preoperative planning for women diagnosed with breast cancer remains controversial. The risks and benefits in women with newly diagnosed ductal carcinoma in situ (DCIS) are largely unknown. Retrospective chart review comparing women treated for DCIS who did and did not undergo MRI for preoperative planning. End points included number of additional biopsies prompted by MRI, surgical reexcision rates, weight of excisions, mastectomy rates, and conversion to mastectomy after attempted breast conservation. 218 patients met study criteria. Sixty-four patients did not undergo preoperative MRI, and 154 patients did. There was no statistically significant difference (P = not significant, NS) in reexcision rates between the 34.1 % (42/123) of women who did and 20/51 (39.2 %) women who did not undergo MRI. Despite use of preoperative MRI, 11/123 women (8.9 %) were converted to mastectomy due to positive margins compared with 4/51 (7.8 %) in the women who did not undergo MRI (P = NS). In women undergoing MRI, average weight of excision at definitive surgery was 49.5 g, while in women who did not undergo MRI, average weight of excision at definitive surgery was 48.7 g. Our data show that MRI does not significantly decrease reexcision rates or conversion to mastectomy after attempted breast-conservation surgery. Based on our findings, we do not believe preoperative MRI adds benefit to the care of this patient population. Prospective trials are necessary to further investigate the risks and benefits of preoperative MRI in women with DCIS.