Evaluation of lung cancer biomarkers profile for the decision of targeted therapy in EBUS-TBNA cytological samples.

Background: Guidelines recommend performing biomarker tests for epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), BRAF and ROS proto-oncogene-1(ROS1) genes and protein expression of programmed death ligand-1(PD-L1) in patients with non-small lung cell carcinoma (NSCLC). Studies reported that endobronchial ultrasound-transbronchial needle aspiration (EBUS-TBNA) can provide sufficient material for cancer biomarker analyses, but there are still concerns about the subject.

Aim: The purpose of the study was to assess the adequacy of EBUS-TBNA for testing lung cancer biomarkers.

Methods: We retrospectively reviewed patients with NSCLC whose EBUS-TBNA was analysed for EGFR, ALK, ROS-1, BRAF and PD-L1 expression between December 2011 and December 2020.

Results: A total of 394 patients were enrolled in the study. EGFR mutation and ALK fusion were the most common studied biomarkers. EBUS-TBNA adequacy rate for biomarker tests was found 99.0% for EGFR, 99.1 for ALK, 97.2% for ROS1, 100% for BRAF and 99.3% for PD-L1 testing. Multivariate analysis revealed the histological type, history of treatment for NSCL, size, or 18-fluorodeoxyglucose uptake of sampled lesion did not show any association with TBNA adequacy for biomarker testing.

Conclusion: EBUS-TBNA can provide adequate material for biomarker testing for EGFR, ALK, ROS-1, BRAF and PD-L1 expression.