Suitability of endobronchial ultrasound-guided transbronchial needle aspiration samples for programmed death ligand-1 testing in non-small cell lung cancer, the Bristol experience

Treatment for non-small cell lung cancer (NSCLC) is now personalised using molecular mutation testing. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) biopsy suitability for anaplastic lymphoma kinase (ALK) and epidermal growth factor receptor (EGFR) mutation testing is established. Less is currently known about EBUS-TBNA suitability for PD-L1 (programmed death ligand-1) testing. To assess EBUS-TBNA biopsy adequacy for ALK, EGFR and PD-L1 testing, we conducted a prospective study of 279 consecutive NSCLC patients referred to a tertiary EBUS-TBNA centre in South West England. One hundred eight-four (62.6%) patients were found to have adenocarcinoma, 83 (28.2%) had squamous cell carcinoma, and 27 (9.2%) were identified as NSCLC-not otherwise specified. EGFR testing was successful in 166 of 168 patients (98.8%), ALK testing in all 115 and PD-L1 testing in 43 of 49 patients (88.2%). Previous EGFR and ALK testing did not affect biopsy PD-L1 testing success. PD-L1 testing failures occurred in three of five (60.0%) of 22G needle biopsies, one of five (20.0%) of 21G needle biopsies and two of 39 (5.1%) of 19G needle biopsies, P = .016. EBUS-TBNA biopsies are mostly suitable for PD-L1 testing. Larger needle size may improve PD-L1 (but not EGFR and ALK) testing success but requires further study in a controlled trial.