Next-generation sequencing for genetic analysis of endobronchial ultrasound transbronchial needle aspiration samples in advanced lung cancer.

Abstract

e15586 Background: Next-generation sequencing (NGS) typically requires greater quantities of DNA than traditional molecular testing. Endobronchial Ultrasound-Guided Transbronchial Needle Aspiration (EBUS-TBNA) is a minimally invasive technique with high sensitivity in the mediastinal staging of lung cancer. This study aimed to evaluate the adequacy of EBUS-TBNA in providing adequate size specimens for genetic mutations and immunotherapy biomarkers analysis in patients with lung cancer. Methods: Tissue samples from patients with advanced lung cancer were collected by EBUS-TBNA and were formalin-fixed paraffin-embedded. NGS assay was carried on with acornmed panel including 808 genes. PD-L1 expression through immunohistochemistry was assessed. Results: A total of 98 patients was enrolled, of which 74 (76%) were adenocarcinoma and 20 (20%) were squamous cell carcinomas. Among the patients, 108 samples (including multipoint puncture of different location and retest of the same patient) were obtained. NGS assay was completed successfully on 106 of the 108 samples (98.14%), and 97.96% of patients had successful testing, identifying an average of 11.3 mutations. With a multi-gene panel comprising up to 808 tumor related genes, actionable variations were found in 93 (86%) samples. Of these, the positive rates of actionable alterations in lung adenocarcinoma samples and lung squamous cell carcinoma samples were 90% and 79%, respectively. The tumor mutation burden (TMB), Microsatellite instability (MSI) and PD-L1 expression were found High in 20 (41%), 1 (2%), and 37 (72%) patients respectively. Conclusions: NGS assay can be successfully conducted with tissue samples obtained from EBUS-TBNA. NGS assay provides more comprehensive information on genetic mutations in tumors, which greatly assists therapeutic decision making for advanced lung cancer.