The role of contrast-enhanced MR mammography for determining candidates for breast conservation surgery

The aim of this study was to assess the impact of preoperative magnetic resonance mammography (MRM) on the surgical determination of breast conservation treatment for breast cancer patients.

From September 1997 to March 2000, 57 consecutive breast conservation treatment candidates were prospectively evaluated with conventional imaging studies (mammography and ultrasonography) and preoperative MRM.

In 47 of 54 (87% ) breast cancer patients breast conservation surgery (BCS) was indicated on the basis of mammography (MMG) and ultrasonography (US). However in 40 of the 54 (74% ) patients BCS was indicated on the basis of MRM. Thirty-eight of the 40 patients ultimately underwent BCS and only 1 showed a positive margin. There were 7 patients whose MRM findings suggested that more aggressive treatment than BCS was needed but for whom US/MMG suggested that BCS was appropriate. Five of the 7 patients underwent mastectomy rather than BCS based on the MRM findings, which were justified by post-surgical histological findings. Of the 2 remaining patients who underwent BCS, one had a positive histological margin and one had recurrence, both of which resulted in salvage mastectomy.

Our study suggests that high resolution preoperative MRM provides more accurate information compared with US and MMG for selecting candidates for BCS. Using MRM as a routine staging tool may reduce unnecessary repeated excisions. A larger study will be required to confirm these findings and to define the patients most likely to benefit from breast MR imaging.