Can supine breast magnetic resonance imaging help hit the target in extreme oncoplastic surgery?

To evaluate the clinical value of supine magnetic resonance imaging (MRI) for tumor localization in breast cancer patients with large or multifocal tumors detected by prone MRI, scheduled for oncoplastic breast conserving surgery (OBCS). Outcomes were compared with those of patients who underwent wide local excision (WLE) or OBCS without MRI guidance.

Over a 2-year period, consecutive patients with large or multifocal disease scheduled for OBCS with MRI-only findings were invited to participate (Group-1). Supplementary supine MRI was performed, and tumor margins were marked in the surgical position. Consecutive patients with early, non-palpable breast cancer who underwent WLE (Group-2) or OBCS (Group-3) were included for comparisons. The primary outcome was reoperation due to an insufficient margin. Secondary outcomes included surgical complications and delayed adjuvant treatment.

Altogether, 102 breasts (98 patients) were analyzed. All preoperative demographic data were comparable among the three groups. Multifocality, tumor-to-breast volume ratio, and the volume of excised breast tissue were significantly greater in Group-1 than in Groups-2 and 3. Operation time was longer and the need for axillary clearance or surgery for both breasts was more common in Groups-1 and 3 than in Group-2. Adequate margins were achieved in all patients in Groups-1 and 2, and one patient underwent re-excision in Group-3.

Supine MRI in the surgical position is a new, promising method to localize multifocal, large tumors visible on MRI. Its short-term outcomes were comparable with those of conventional WLE and OBCS.