Pilot Study of the Performance of 19-G Needle in Endobronchial Ultrasound-guided Transbronchial Aspiration for the Diagnosis and Testing of Molecular Markers in Lung Cancer.

Abstract

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has become the standard for diagnosis and staging of lung cancer. Historically, 21- and 22-G needles have been paired with EBUS. We evaluated the performance of EBUS-TBNA using a larger 19-G needle in the assessment of tumor tissue obtained and success of testing for molecular markers. We prospectively enrolled adult patients with lymphadenopathy concerning for metastatic lung cancer. Patients underwent diagnostic EBUS-TBNA utilizing 19-G needles. Cases of non-small cell lung cancer (NSCLC) were evaluated for programmed cell death receptor ligand (PD-L1) expression. Cases of adenocarcinoma or undifferentiated NSCLC were further evaluated for 3 molecular markers for driver mutations: epidermal growth factor receptor (EGFR), c-ros oncogene 1 (ROS-1), and anaplastic lymphoma kinase (ALK). Fifty patients were enrolled and underwent EBUS-TBNA using 19-G needles. PD-L1 assay was successfully performed in 90% of NSCLC cases. In adenocarcinoma or undifferentiated NSCLC cases, the success rate in testing was 90% for EGFR and 86% for ALK. ROS-1 testing had a success rate of 67%; 24% of these specimens had adequate tumor cells but there was technical difficulty with the assay. Block quality was judged by total number of tumor cells per hematoxylin and eosin-stained slide of each cell block (58% of specimens had >500 cells and 22% had 200 to 500 cells). There were no adverse events. EBUS-TBNA using 19-G needles can obtain a high number of tumor cells and has a high rate of success in performing assays for PD-L1, EGFR, and ALK in NSCLC patients without an increase in adverse events. The success rate of ROS-1 testing was lower.