Is the learning curve of robotic low anterior resection shorter than laparoscopic low anterior resection for rectal cancer?: a comparative analysis of clinicopathologic outcomes between robotic and laparoscopic surgeries

Abstract

As robotic surgery was developed with ergonomic designs, there are expectations that the technical advantages of robotic surgery can shorten the learning curve. However, there is no comparative study, so far, to evaluate the learning curve between robotic and laparoscopic rectal cancer surgeries. Therefore, the aim of this study is to compare the learning curve of robotic low anterior resection (LAR) with laparoscopic LAR for rectal cancer.Patients who underwent robotic or laparoscopic LAR by a single surgeon were compared retrospectively (robot n = 89 vs laparoscopy n = 89). Cumulative sum (CUSUM) was used to evaluate the learning curve. The patients were divided into phase 1 (initial learning curve period) and phase 2 (post-learning curve period). The perioperative clinicopathologic characteristics were compared by phases and surgical procedures.According to CUSUM, the learning curve of robotic LAR was the 44th case and laparoscopic LAR was the 41st case. The learning phases were divided as follows: phase 1 (cases 1-41) versus phase 2 (cases 42-89) in the laparoscopic group, and phase 1 (cases 1-44) versus phase 2 (cases 45-89) in the robotic group. Comparison between phase 1 and phase 2 in each type of surgery showed no significant difference for the perioperative outcomes. Comparison between robotic and laparoscopic surgeries in each phase showed similar perioperative results. Pathologic outcomes were not significantly different in both procedures and phases.The learning curve of robotic LAR for rectal cancer was similar to laparoscopic LAR, and the clinicopathologic outcomes were similar in both the procedures.

FIGURE 1

Flow chart of patient selection. TAH-BSO = total abdominal hysterectomy with bilateral salpingo-oopherectomy.

FIGURE 2

Moving average method for the operation time. (A) Total operation times of laparoscopic (n = 89) and robotic surgery (n = 89); the first peak point of robotic surgery is the 21st case, the second point, the 67th case. (B) SCT and docking time of robotic surgery; the first peak point of SCT is the 19th case, and the second peak point, the 63rd case. SCT = surgeon console time.

FIGURE 3

CUSUM for the operation time. (A) CUSUM for the total operation time of laparoscopy and robot; the peak point of CUSUM in laparoscopic surgery was the 41st case, and in robotic surgery, the 45th case. (B) CUSUM graph of SCT and docking time in robotic surgery; The peak point of the CUSUM was the 44th case of SCT, and the 21st case of docking time. CUSUM = cumulative sum, SCT = surgeon console time.

FIGURE 4

CUSUM comparison for the total operation time between robotic surgery (n = 130) and laparoscopic surgery (n = 89); the peak points of CUSUM in both procedures did not change with the original results using the same number of robotic and laparoscopic cases (n = 89). CUSUM = cumulative sum.