Learning Curve and Surgeon Experience in En Bloc Transurethral Resection of Bladder Tumour: A Retrospective Cohort Study

BACKGROUND: En bloc transurethral resection of bladder tumour (ERBT) has been increasingly adopted to improve pathological accuracy and reduce recurrence rates compared with conventional TURBT. However, the influence of surgeon experience on procedural quality, oncologic outcomes, and learning curve dynamics remains underexplored. METHODS: A retrospective cohort study was performed on 80 consecutive patients undergoing ERBT between 2018 and 2024 at Palmerston North Hospital. Surgeons were stratified by experience (< 100 vs. ≥ 100 prior ERBTs). Primary outcomes included detrusor muscle presence, margin positivity, recurrence, and progression rates. Secondary analysis employed cumulative sum (CUSUM) and rolling mean analyses to evaluate the procedural volume required for competency. RESULTS: Detrusor muscle was present in 82% of specimens, with no significant difference between high- and low-experience surgeons (79% vs. 84%, p = 0.77). Recurrence (27% vs. 37%, p = 0.14), progression (11% vs. 3%, p = 0.26), and complication rates (8% vs. 6%, p = 1.00) were comparable. CUSUM analysis indicated consistent detrusor muscle sampling after 14 cases, while operative efficiency improved and stabilized after 17 cases. Mean operative efficiency was 2.07 ± 1.13 min/mm overall, and high experienced surgeons demonstrated greater efficiency (1.71 ± 0.89 vs. 2.64 ± 1.24 min/mm). CONCLUSION: ERBT is a safe and reproducible procedure that can be effectively performed by supervised trainees with outcomes equivalent to those of senior surgeons. Competency appears to be achieved after approximately 14-17 cases. These findings support the integration of ERBT into structured urological training programmes as a model for competency-based education.