Learning curves and association of pathologist’s performance with the diagnostic accuracy of linear endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA): a cohort study in a tertiary care reference centre

OBJECTIVES: We aimed to assess the learning curves and the influence of the pathologist’s performance on the endobronchial ultrasound transbronchial needle aspiration’s (EBUS-TBNA’s) diagnostic accuracy in a real-world study. DESIGN/SETTING: Cohort study conducted in a tertiary care university hospital (single centre) with patients referred for EBUS-TBNA. PARTICIPANTS/INTERVENTION: We initially evaluated 376 patients (673 lymph nodes), 368 (660 lymph nodes) of whom were recruited. The inclusion criterion was EBUS-TBNA indicated for the study of mediastinal or hilar lesions. The exclusion criteria were the absence of mediastinal and hilar lesions during EBUS confirmed by a normal mediastinum and hilum on chest CT (except in cases of mediastinal staging of cancer) and lost to follow-up. PRIMARY AND SECONDARY OUTCOME MEASURES: Diagnostic accuracy and related outcomes. METHODS: We included patients from a prospectively constructed database. We performed a logistic regression multivariate analysis to adjust for potential confounders of the association between pathologist performance and EBUS-TBNA accuracy. The Cumulative Summation (CUSUM) analysis was used to assess pathologists’ performance and learning curves. RESULTS: Most indications for EBUS were suspicion of malignancy, including intrathoracic tumours (68.3%), extrathoracic tumours (9.8%) and cancer staging (7.0%). The patients’ mean age was 63.7 years, and 71.5% were male. Overall EBUS-TBNA accuracy was 80.8%. In the multivariate logistic regression model, the factors independently associated with EBUS-TBNA accuracy included certain pathologists (ORs ranging from 0.16 to 0.41; p<0.017), a lymph node short-axis diameter <1 cm (OR: 0.36; 95% CI 0.21 to 0.62; p<0.001), and the aetiology of lymph node enlargement (ORs ranging from 7 to 37; p<0.001). CUSUM analysis revealed four different learning curve patterns, ranging from almost immediate learning to a prolonged learning phase, as well as a pattern consistent with performance attrition. CONCLUSIONS: Pathologists’ proficiency conditioned EBUS-TBNA accuracy. This human factor is a potential source of error independent of factors conditioning tissue sample adequacy.