Sensitivity of Linear Endobronchial Ultrasonography and Guided Transbronchial Needle Aspiration for The Identification of Nodal Metastasis in Lung Cancer Staging

Abstract 

The aim of this study is to determine the sensitivity of real-time endobronchial ultrasonography (EBUS)-guided transbronchial needle aspiration (TBNA) in lung cancer staging. Short- and long-axis node diameters were measured during EBUS in patients referred for lung cancer staging and sensitivities for the identification of nodal malignancy at TBNA determined. Three hundred fifteen real-time EBUS-guided TBNA nodal sampling procedures were performed in 161 patients and in 87 of them, N2/N3 metastasis was confirmed (50.9%), eliminating the need for mediastinoscopy. The median (interquartile range [IQR]) short-axis diameters of the sampled mediastinal and lobar nodes were 11 (8–15) and 8 (7–12) mm, respectively. TBNA provided satisfactory samples from 269 nodes (85.4%) and a sensitivity of 100% for the identification of malignant TBNA samples was reached for a short-axis diameter cut-off of 5 mm and a short- to long-axis ratio of 0.5. The probability of malignancy was over 90% for nodes with a short-axis diameter >20 mm and 55% for round nodes (short- to long-axis ratio of 1). In 18 out of 50 patients with a normal mediastinal computed tomography (CT) scan, the technique identified enlarged nodes in the mediastinum (36%), mainly in the subcarinal region and confirmed mediastinal malignancy in 8 (10%). Real-time EBUS-guided TBNA obtains satisfactory node samples in almost 90% of cases and improves the identification of enlarged nodes in patients with a normal mediastinum at CT. If sampling all nodes with a short-axis diameter of ≥5 mm and a short- to long-axis ratio ≥0.5, a sensitivity of 100% for the cytologic identification of malignant nodes can be expected. (Email: ignasigo@separ.es)

Key Words: Endobronchial ultrasonography, EBUS, Real-time transbronchial needle aspiration, TBNA, Lung cancer, Staging, Node morphology, Sensitivity