Ultrasound-Assisted Tumor Surgery in Breast Cancer - A Prospective, Randomized, Single-Center Study (MAC 001).

Purpose:  Breast-conserving therapy is associated with a risk of tumor-involved margins. For intraoperative orientation, non- palpable or indistinctly palpable lesions are wire-marked prior to surgery. Ultrasound-guided surgery has the potential to reduce the number of tumor-involved margins. In the MAC 001 trial we evaluated ultrasound-guided breast-conserving surgery compared to wire-guided surgery with regard to free tumor margins, duration of surgery and resection volume.

Materials And Methods:  In this randomized, prospective, single-center controlled trial, patients with ductal invasive breast cancer were recruited for either ultrasound-guided or wire localization surgery. Primary outcomes were tumor-free resection margins, the reoperation rate and the resection volume in each group. The results were analyzed by intention to treat. The trial was registered under ClinicalTrials.gov NCT02222675.

Results:  56 patients were assessed, and 47 patients were evaluated in the trial. 93 % (25/27) of the patients in the ultrasound arm had an R0 reoperation compared to 65 % (13/20) in the wire localization control arm. This result was statistically significant (p = 0.026). No statistical difference was found for the resection volume or the duration of surgery between the two arms. No major complication was seen in either arm.

Conclusion:  Ultrasound-assisted breast surgery significantly increases the possibility of tumor-free margins and therefore reduces the risk of reoperations. Breast surgeons should be trained in ultrasound and ultrasound should be available in every breast surgery operating room.