＜Editors' Choice＞ Learning curve of robotic lobectomy for lung malignancies by certified thoracic surgeons.

Video-assisted thoracic surgery (VATS) has become widespread in the last 20 years, followed by robot-assisted thoracic surgery (RATS). Few studies compared the learning curve between RATS lobectomy and conventional VATS. This study included 79 RATS lobectomy cases performed in our hospital from November 2015 to October 2019. To estimate the required number for learning, the cumulative sum method, which is to plot a value obtained by sequentially accumulating a difference from a mean value was applied. As a result, the median total operative time and the median console time for all cases were 167 minutes and 138 minutes, respectively. Firstly, for our team, 28 cases were estimated to be required for learning curve for RATS lobectomy. For individual, each surgeon might be learned in only 5 to 6 cases. By contrast, the number of cases for learning VATS lobectomy which was underwent by a 'single' surgeon from 2009 was estimated to be 35 cases. The time to dock from start operation (median 14 minutes) reached plateau in 18 cases, but the time after rollout was median of 18 minutes and there was no significant change from the beginning. In conclusion, RATS lobectomy might be a technique that could be learned in a small number of cases compared to VATS. The results of this study might be helpful for certified surgeons who tried to get started with RATS and for establishing a learning program.