The Learning Curve for Robotic Lateral Pelvic Lymph Node Dissection for Rectal Cancer: A View From the West

BACKGROUND: Lateral pelvic lymph node dissection is performed for selected patients with rectal cancer with persistent lateral nodal disease after neoadjuvant therapy. This technique has been slow to be adopted in the West because of concerns regarding technical difficulty. This is the first report on the learning curve for lateral pelvic lymph node dissection in the United States or Europe. OBJECTIVE: This study aimed to analyze the learning curve associated with robotic lateral pelvic lymph node dissection. DESIGN: Retrospective observational cohort. SETTING: Tertiary academic cancer center. PATIENTS: Consecutive patients from 2012 to 2021. INTERVENTION: All patients underwent robotic lateral pelvic lymph node dissection. MAIN OUTCOME MEASURES: The primary end points were the learning curves for the maximum number of nodes retrieved and urinary retention, which was evaluated with simple cumulative sum and 2-sided Bernoulli cumulative sum charts. RESULTS: Fifty-four procedures were included. A single-surgeon learning curve (n = 35) and an institutional learning curve are presented in the analysis. In the single-surgeon learning curve, a turning point marking the end of a learning phase was detected at the 12th procedure for the number of retrieved nodes and at the 20th procedure for urinary retention. In the institutional learning curve analysis, 2 turning points were identified at the 13th procedure, indicating progressive improvements for the number of retrieved nodes, and at the 27th procedure for urinary retention. No sustained alarm signals were detected at any time point. LIMITATIONS: The retrospective nature, small sample size, and the referral center nature of the reporting institution may limit generalizability. CONCLUSIONS: In a setting of institutional experience with robotic colorectal surgery, including beyond total mesorectal excision resections, the learning curve for robotic lateral pelvic lymph node dissection is acceptably short. Our results demonstrate the feasibility of the acquisition of this technique in a controlled setting, with sufficient case volume and proctoring to optimize the learning curve.