Determinants of false-negative results in non-small-cell lung cancer staging by endobronchial ultrasound-guided needle aspiration

Objectives: False-negative results of endobronchial ultrasound-guided transbronchial needle aspiration in non-small-cell lung cancer staging have shown significant variability in previous studies. The aim of this study was to identify procedure- and tumour-related determinants of endobronchial ultrasound-guided transbronchial needle aspiration false-negative results.

Methods: We conducted a prospective study that included non-small-cell lung cancer patients staged as N0/N1 by endobronchial ultrasound-guided transbronchial needle aspiration and undergoing therapeutic surgery. The frequency of false-negative results in the mediastinum was calculated. Procedure-related, first, and tumour-related, second, determinants of false-negative results in stations reachable and non-reachable by endobronchial ultrasound were determined by multivariate logistic regression.

Results: False-negative endobronchial ultrasound-guided transbronchial needle aspiration results were identified in 23 of 165 enrolled patients (13.9%), mainly in stations reachable by endobronchial ultrasound (17 cases, 10.3%). False-negative results were related to the extensiveness of endobronchial ultrasound sampling: their prevalence was low (2.4%) when sampling of three mediastinal stations was satisfactory, but rose above 10% when this requirement was not fulfilled (P = 0.043). In the multivariate analysis, abnormal mediastinum on computer tomography/positron emission tomography [odds ratio (OR) 7.77, 95% confidence interval (CI) 2.19-27.51, P = 0.001] and extensiveness of satisfactory sampling of mediastinal stations (OR 0.37, 95% CI 0.16-0.89, P = 0.026) were statistically significant risk factors for false-negative results in stations reachable by endobronchial ultrasound. False-negative results in non-reachable nodes were associated with a left-sided location of the tumour (OR 10.11, 95% CI 1.17-87.52, P = 0.036).

Conclusions: The presence of false-negative ultrasound-guided transbronchial needle aspiration results were observed in nearly 15% of non-small-cell lung cancer patients but in only 3% when satisfactory samples were obtained from three mediastinal stations. False-negative results in stations reachable by endobronchial ultrasound were associated with the extensiveness of sampling, and in stations out of reach of endobronchial ultrasound with left-sided tumours. These results suggest that satisfactory sampling of at least three mediastinal stations by EBUS-TBNA may be a quality criterion to be recommended for EBUS-TBNA staging.