# Defining the learning curve for thulium Laser en bloc resection of bladder tumors: a single-surgeon retrospective cohort study

## TL;DR

This study identifies a learning curve of 32 procedures for a surgeon to become proficient in a new laser-based bladder tumor removal technique.

## Contribution

Quantifies the learning curve for TL-ERBT using objective metrics and statistical analysis in an experienced surgeon's practice.

## Key findings

- Proficiency in TL-ERBT was achieved after 32 procedures with significantly reduced operation time.
- Conversion to conventional TURBT decreased from 12.5% to 2.1% after reaching proficiency.
- Detrusor muscle presence and complication rates remained consistent between learning and proficiency phases.

## Abstract

To quantitatively analyze the learning curve for thulium laser en bloc resection of bladder tumor (TL-ERBT) performed by a surgeon experienced in conventional transurethral resection of bladder tumor (TURBT).

In this single-surgeon, retrospective cohort study, the initial 86 consecutive TL-ERBT cases were reviewed. Operation time was used as the primary outcome. Learning curve analysis was performed using moving average and cumulative sum (CUSUM) methods.

Among 79 successfully completed TL-ERBTs, the mean operation time was 31.6 ± 10.3 min. CUSUM analysis identified a turning point at case 32, separating the Learning phase (cases 1–32) from the Proficiency phase (cases 33–86). Operation time significantly decreased from 37.8 ± 9.2 min in the Learning phase to 27.8 ± 8.1 min in the Proficiency phase (P < 0.001). The conversion rate to conventional TURBT declined from 12.5% to 2.1% (P = 0.038). Detrusor muscle presence in specimens (87.3% overall) and major complication rates were comparable between phases.

For a surgeon experienced in conventional TURBT, preliminary evidence from this study suggests that proficiency in TL-ERBT, defined primarily by operative efficiency, may be achievable after approximately 32 procedures, with significant improvements in operative efficiency and technical success; while patient safety was not compromised. These findings provide a practical quantitative benchmark for surgical training and clinical implementation.