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

https://doi.org/10.1016/j.ultrasmedbio.2009.03.007Get rights and content

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: [email protected])

Introduction

Endobronchial ultrasonography (EBUS) is a recently introduced technique that improves transbronchial needle aspiration (TBNA) results in lung cancer staging thanks to the visualization of mediastinal and lobar lymph nodes. The use of radial EBUS before TBNA has increased the sensitivity of the technique above 80%, mainly through an increase in the accuracy of upper and left paratracheal nodal sampling (Herth et al., 2003, Herth et al., 2004). Linear EBUS with real-time TBNA has further improved results through the performance of TBNA under direct ultrasonographic visualization, an approach that allows noninvasive sampling of nodes with high sampling accuracy regardless of nodal size (Krasnik et al., 2003, Rintoul et al., 2005, Yasufuku et al., 2004a, Yasufuku et al., 2005a, 2005).

The aim of the present study was to determine the usefulness of the lymph node morphologic appearance during real-time EBUS-guided TBNA in patients referred for lung cancer staging who show both enlarged or normal-appearing mediastinal lymph nodes in computed tomography (CT) scans, in terms of the sensitivities and relationships of EBUS-measured lymph node diameters with nodal malignancy identified at TBNA sampling and the frequency of identification of mediastinal nodes with a short-axis diameter over 10 mm during EBUS in patients with a normal mediastinum at their CT scan.

Section snippets

Population

We performed a prospective study including all patients who were referred for lung cancer staging through real-time EBUS-guided TBNA to the North Barcelona Lung Cancer Unit between 2005 and 2007. A CT scan of the lung, mediastinum and upper abdomen was performed in all cases using a multidetector-row spiral CT scanner (Marconi M8000; Phillips, Best, The Netherlands) in the month prior to staging and mediastinal nodes with a short-axis diameter greater than 10 mm in the scan were considered to

Population

The number of patients referred to the North Barcelona Lung Cancer Unit for lung cancer diagnosis and/or staging in the period of study was 370. Real-time EBUS-guided TBNA was used for staging in 171 patients with lung cancer who required mediastinal and lobar lymph node sampling and did not have any contraindication for the performance of the procedure. A total of 121 of these patients (70.0%) had mediastinal nodes with a small-axis diameter greater than 10 mm on the CT scan (Table 1). In 10

Discussion

Our study confirms that EBUS-guided TBNA is an appropriate technique for sampling mediastinal and lobar lymph nodes in lung cancer staging, in patients with either abnormal or normal mediastinal CT scans, and shows that the procedure is able to identify mediastinal malignancy in more than half of the studied patients. Our findings also show that in order to ensure maximum sensitivity, all accessible nodes with a short-axis diameter of 5 mm or more and a short- to long-axis ratio of 0.5 or

Acknowledgements

The authors thank Adoración Ruiz for her technical assistance during the performance of the procedures. Anne Murray and M. E. Kerans assisted with the English language. This study was supported by funds from the CIBER de Enfermedades Respiratorias–CibeRes, Fondo de Investigación Sanitaria FIS 070170, Sociedad Española de Neumología y Cirugía Torácica (SEPAR), Societat Catalana de Pneumologia, ACT 2008 and Asociación Española de Endoscopia Respiratoria (AEER), CIBER de Enfermedades

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