Learning Diagnostic Proficiency in Robotic-Assisted Bronchoscopy with Integrated Cone-Beam CT: A 680-Lesion Learning Curve Analysis

Background. Robotic-assisted bronchoscopy combined with integrated cone-beam computed tomography (RAB+CBCT) enables accurate sampling of peripheral pulmonary lesions (PPLs), but the acquisition of diagnostic proficiency and program-level efficiency remains incompletely characterized. Methods. We conducted a single-center cohort study of consecutive RAB+CBCT (Ion endoluminal system, Cios Spin) procedures performed by two experienced interventional pulmonologists. Strict lesion-level diagnostic yield was the primary outcome. Learning curve cumulative sum (LC-CUSUM) analysis determined operator-specific proficiency, followed by conventional CUSUM monitoring of post-proficiency performance. Secondary outcomes included procedure and intubation times, temporal changes in case complexity, and adverse events. Results. Overall, 427 procedures comprising 680 PPLs were analyzed. Median lesion long-axis diameter was 11 mm, 14.4% had a bronchus sign, and 36.5% of procedures involved multiple lesions. Strict lesion-level diagnostic yield was 85.4% (581/680). LC-CUSUM demonstrated proficiency after 48 and 86 PPLs, respectively; thereafter, both operators maintained acceptable performance without crossing the predefined CUSUM decision limit. Median procedure time decreased from 65 minutes during the first 10 procedures to 38 minutes during the last 10. The median intubation time was 70 minutes and declined significantly with increasing experience. Most indicators of lesion complexity remained stable, while short-axis diameter and bronchus-sign prevalence decreased modestly. Adverse-event frequency declined significantly over time. Conclusion. RAB+CBCT achieved high strict diagnostic yield, with heterogeneous operator-specific learning trajectories within a maturing multidisciplinary program. Diagnostic performance, procedural efficiency, and safety improved despite stable or modestly increasing case complexity. These findings support individualized, outcome-based proficiency assessment and longitudinal monitoring, rather than comparative operator ranking or reliance on fixed procedural-volume thresholds.