The Performance of an Extended Next Generation Sequencing Panel Using Endobronchial Ultrasound-Guided Fine Needle Aspiration Samples in Non-Squamous Non-Small Cell Lung Cancer: A Pragmatic Study

Introduction/background: Samples from endobronchial ultrasound-guided fine needle aspiration (EBUS-TBNA) are frequently used for next generation sequencing (NGS) in patients with non-small cell lung cancer (NSCLC) to look for genetic driver mutations. The objective of the current study was to evaluate the performance of extended NGS panels using EBUS-TBNA samples in a real-world setting and identify factors associated with the success of NGS.

Materials and methods: This study included all patients who underwent EBUS and were diagnosed with non-squamous NSCLC with mediastinal metastasis from 2016 to 2019 at the University of Pennsylvania. We reviewed demographic information, imaging studies, procedure reports, pathology and NGS reports. Logistic regression was used to analyze factors associated with the success of NGS panels.

Results: The success rates of NGS using EBUS-TBNA samples were 92.5%, and 91.5% for DNA and RNA NGS panels respectively. Samples from higher N stage (N2 and N3 lymph nodes) and with higher tumor cellularity (>25%) resulted in higher success rate for DNA NGS. The effect of tumor cellularity remained borderline significant after entering multivariable logistic regression. The short-axis diameter of the sampled lymph node on CT scan, FDG-avidity on PET CT and >3 EBUS passes per lymph node during the procedure were not associated with NGS success.

Conclusion: Both DNA and RNA extended-panel NGS had high performance using EBUS-TBNA samples. Sampling more advanced nodal stations and obtaining samples with higher tumor cellularity were associated with higher success rate of DNA NGS. Other imaging or procedural factors did not affect NGS performance.