The Learning Curve of Reverse-Sequence Endoscopic Nipple-Sparing Mastectomy with Immediate Prepectoral Implant Reconstruction: CUSUM Analysis.

Background: The reverse-sequence endoscopic nipple-sparing mastectomy with immediate prepectoral implant reconstruction (RSEM-IPI) has been described as a safe and feasible procedure for early-stage breast cancer. The aim of this study was to evaluate the learning curve for RSEM-IPI. Methods: Between January 2023 and February 2024, we collected data on 104 consecutive patients who underwent RSEM-IPI at our hospital (53 for group 1 and 51 for group 2). The surgeons in group 1 completed the endoscopic training and assistance, whereas the surgeons in group 2 did not. The learning curve was analyzed using the cumulative sum (CUSUM) method to assess changes in the operative times across the case sequence. Results: Among the 281 patients who received breast reconstruction surgeries, a total of 104 consecutive data were recorded and eligible. Both groups had higher rates of postoperative complications including bleeding, nipple-areolar complex (NAC) ischemia, skin ischemia, infection and longer drainage duration during the phrase 1 compared to the phrase 2. Notably, in terms of the most severe postoperative complications, implant expose and loss, both groups exhibited higher rates during the phrase 1. Breast-Q scores for group 1 in phases 1 and 2 were 66 and 84, respectively, while for group 2, they were 67 and 80. As compared with surgeons in group 2, well-trained surgeons in group 1 were more accessible for stable learning curve with fewer training patients (18 patients) and relatively lower rate of postoperative complications ( Conclusion: The estimated learning curve for RSEM-IPI was achieved after 18 cases in the well-trained surgeon group. The endoscopic training and assistance were critical to master the breast endoscopic surgeries for breast surgeons.