The learning curve of robotic nipple sparing mastectomy for breast cancer: An analysis of consecutive 39 procedures with cumulative sum plot.

BACKGROUND: The preliminary experience and learning curve of robotic nipple sparing mastectomy (R-NSM) in the management of breast cancer were analyzed and reported. METHODS: The medical records of patients who underwent R-NSM for breast cancer during the period of March 2017 to June 2018 were collected from the same surgeon in a single institute. Data on clinicopathologic characteristics, type of surgery, method of breast reconstruction, and operation time were prospective collected. Learning curve of R-NSM was evaluated and analyzed by the cumulative sum (CUSUM) plot method. RESULTS: A total of 39 consecutive R-NSM procedures from 35 patients were analyzed. The time needed for "docking", "R-NSM", and "R-NSM and immediate prosthesis breast reconstruction (IPBR)" decreased after cases experience accumulated, and in mature phase procedures could finished within 10 min, 100mins, and 240 min, separately. In CUSUM plots analysis of learning curve, the cases needed to decrease operation time for "docking", "R-NSM", and "total time for R-NSM and IPBR" were 13th, 13th, and 12th procedures separately. Mastectomy weight and lymph node metastasis were factors related to operation time. The rate of total nipple areolar complex necrosis for R-NSM was 0%. One (2.9%, 1/35) R-NSM procedure was found to have positive margin involved in the final pathologic check-up. No implant loss, or local recurrence was observed during a mean follow-up of 8.6 ±â€¯4.5 (1.3-16.7) months. CONCLUSION: From our preliminary experience, R-NSM and IPBR (or R-NSM alone) is a safe procedure, and the operation time needed significantly decrease after cases experience accumulated.