An initial experience of robot-assisted breast conserving surgery: A multicenter study of the Korea Robot-Endoscopy Minimal Access Breast Surgery Study Group (KoREa-BSG).

543 Background: Robot-assisted breast conserving surgery (RABCS) have cosmetic benefit without any scar on the breast over conventional breast conserving surgery (CBCS). However, data on the feasibility and safety of the RABCS are limited. The aim of this study was to present the results of early experience of RABCS. Methods: A multi-center retrospective review was conducted to identify women who underwent RABCS as part of the Korea Robot-Endoscopy & Minimal Access Breast Surgery Study Group (KoREa-BSG) between August 2019 and October 2023. Information of the clinicopathologic characteristics, perioperative complications, operation time, recurrence, and re-operation were collected. Results: A total of150 patients underwent the RABCS procedure conducted by 10 breast surgeons at seven institutions. Invasive breast cancer was noted in 121 cases and ductal carcinoma in-situ was detected in 29 cases. Further, 75.3% and 65.3% of the patients had an estrogen and progesterone receptor positive status, respectively. A total of 35.3% of the patients had a HER2-positive status. In terms of the surgical technique, the Da Vinci SP system was more frequently used (60%). Gas insufflation was applied in 97.33% of the cases, and s entinel lymph node biopsy (SLNB) only was the most common axillary surgery (89.3%). The median duration of postoperative days was 5.4 days (range, 1.0-15.0 days). The incision location was the mid-axillary line and the median incision length was 37.1 mm (range, 27.0-60.0 mm). The median total operation time was 133.8 minutes (range, 62.0-295.0 minutes). 11 cases (7.3%) showed frozen margin positive, however only one case (0.7%) required re-operation because of permanent margin positive. Six patients (4%) developed surgical complications. Postoperative bleeding was found in one case and skin burn was found in five cases (3.3%); two cases (1.3%) required skin excision and three cases (2.0%) showed spontaneous resolution. There were no cases of conversion to open surgery or mortality. Only one case (0.7%) had recurrence. Conclusions: This was the first multicenter report of RABCS in the world. RABCS could be a technically feasible and safe. Further subsequent comparative study with CBCS and prospective research are needed to evaluate the surgical and oncologic outcomes.