MRI-Guided Quadrantectomy in Patients with Ductal Carcinoma in Situ Detected Preoperatively by Mammographic Calcifications

BACKGROUND: We designed MRI-guided quadrantectomy using 2-dimensional images reconstructed from MRI to enable virtual simulation of breast-conserving surgery. This study evaluated the efficacy of our approach, which involved projection of the 2-dimensional reconstruction images directly onto the breast to guide planned resection compared with the conventional approach with preoperative localization with hooked wires, for patients with ductal carcinoma in situ (DCIS) detected by mammographic calcifications. STUDY DESIGN: Eighty-six patients with calcifications ≥2 cm in diameter on mammogram who were diagnosed with DCIS on preoperative percutaneous biopsy underwent breast-conserving surgery. In 32 patients, lesion localization was done using the conventional technique of hooked wires. In 54 patients, preoperative planning was performed using supine MRI and projection of reconstructed 2-dimensional images directly onto the breast surface. Surgical outcomes in the 2 groups were compared. In the latter group, we also compared accuracy of DCIS detection between supine MRI and specimen mammography. RESULTS: Final pathologic assessment of the 86 patients was DCIS in 67 and DCIS with microinvasion (T1mic) in 19 patients. The rate of additional intraoperative margin resection and presence of DCIS at the surgical margin were significantly lower with our MRI-guided technique vs the hooked-wire approach. Supine MRI detected a considerably larger area of DCIS than did specimen mammography. CONCLUSIONS: Compared with a conventional approach using hooked wires, our MRI-guided quadrantectomy might be useful for patients with DCIS and DCIS with T1mic detected by mammographic calcifications, due to the superior ability to detect DCIS on MRI compared with mammography.