Interaction Between Operator and Assistant Certification Is Associated With Local Recurrence After Laparoscopic...

Local recurrence (LR) after laparoscopic rectal cancer surgery remains a major clinical concern. While surgical expertise is important, the impact of combined operator and assistant certification on local recurrence remains unclear.

This retrospective multicenter study analyzed 2825 patients with stage II-III rectal cancer who underwent laparoscopic resection in the EnSSURE cohort. The primary endpoint was the 3-year cumulative incidence of LR, treating death and distant metastasis as competing events. The primary analysis used a Fine-Gray model including an interaction term between operator and assistant certification based on the Endoscopic Surgical Skill Qualification System. Secondary analyses included a four-group Fine-Gray analysis (qualified operator and assistant [QQ], qualified operator only [QN], qualified assistant only [NQ], and neither qualified [NN]). A cause-specific Cox model was used for sensitivity analysis.

During a median follow-up of 55 months, LR occurred in 125 patients (4.4%). A significant interaction between operator and assistant certification was observed (subdistribution hazard ratio [sHR] 0.43, 95% confidence interval [CI] 0.20-0.95; p = 0.038), whereas neither was independently associated with LR. In the four-group analysis, the risk of LR was significantly higher in the QN, NQ, and NN groups compared with the QQ group (QN: sHR 2.37; NQ: sHR 2.12; NN: sHR 2.18). Results were consistent in sensitivity analyses.

A significant interaction between operator and assistant certification was associated with a lower risk of LR, suggesting that surgical outcomes may depend on team composition rather than individual qualifications alone.

UMIN Clinical Trials Registry System: UMIN000040645 (June 3, 2020).