Learning Curve on Lymph Nodes Retrieval and Postoperative Length of Hospital Stay in Robotic Rectal Cancer: A Retrospective, Observational Study.

Background and Aims: Robotic rectal cancer surgery has been introduced to reduce the difficulty and complications of the procedure. This study aims to assess the learning curve for robotic rectal cancer of individual surgeons with extensive laparoscopic rectal cancer surgery through multidimensional analyses. Methods: Data were retrospectively collected on 156 patients who underwent robotic rectal cancer surgery by a single surgeon between January 2018 and December 2023. Results: The operative time required for LAR can be divided into three distinct phases: an early or learning phase (1-24 cases), an intermediate or proficient phase (25-55 cases), and a late or mastery phase (56-72 cases). The study found that the learning curve for LAR and protective operative time can be divided into three distinct phases: an early or learning phase (1 to 15 cases), an intermediate or proficient phase (16 to 40 cases), and a late or mastery stage (41 to 63 cases). Following the completion of 46 cases of surgery, the next stage of the learning curve for lymph nodes retrieval has been reached. The discrepancy between the mean number of lymph nodes retrieved in each of the three stages was marginal, with an difference of 0.5 between the lowest and highest values observed (14.1 vs. 13.6 vs. 13.7). The length of hospital stay for patients decreases as the surgeon gains more experience, reaching a mean of 10.3 days in 2023. Conclusion: This study shows that robotic surgery for rectal cancer has a significant learning curve with multiple stages. Robotic surgery can remove more lymph nodes than recommended by guidelines even during the learning phase (recommend that at least 12 lymph nodes should be retrieved). As the learning curve progresses to the mastery phase, the length of postoperative hospital stays gradually decreases to a lower level.