The Efficacy of EBUS-Guided Transbronchial Needle Aspiration for Molecular Testing in Lung Adenocarcinoma

Abstract

The purpose of the study was to assess the efficacy of obtaining adequate cytologic specimens by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for molecular testing of lung adenocarcinomas. This was an institutional review board-approvedstudy of all patients who had undergone EBUS-TBNA from April 2010 through March 2012 for the diagnosis, staging, or both of lung cancer. Patients with a diagnosis of adenocarcinoma were reflexively tested for molecular markers by polymerase chain reaction, sequencing, and fluorescence in situ hybridization (FISH). All procedures were performed with patients under conscious sedation in the bronchoscopy suite. Of 205 patients who underwent EBUS-TBNA, 56 patients (24 male, 32 female) had a diagnosis of adenocarcinoma warranting molecular analysis. Molecular analysis was available for epidermal growth factor receptor (EGFR), Kirsten rat sarcoma (Kras) mutation, and anaplastic lymphoma kinase (ALK) gene rearrangement. The institution's clinical protocol involved initial testing for EGFR mutation with a reflex Kras test if the EGFR test result was negative. ALK FISH molecular testing was completed if both EGFR and Kras test results were negative. A total of 52 of 56 (93%) patients had sufficient cytologic material for complete or partial molecular testing, whereas 46 of 56 (82%) patients had sufficient material for all clinically indicated testing. EGFR, Kras, and ALK analysis yielded positive results in 5 (10%), 10 (25%), and 5 (12%) tested specimens, respectively. No complications were associated with EBUS-TBNA. EBUS-TBNA performed with the patient under moderate sedation can be expected to yield sufficient tissue for sequential molecular analysis in the majority of patients. In an era of targeted therapy for lung adenocarcinomas, EBUS-TBNA is effective in clinical practice for complete diagnosis, staging, and treatment planning in these patients.