Programmed death-ligand 1 testing of lung cancer cytology specimens obtained with bronchoscopy

Abstract

BACKGROUND: Programmed death-ligand 1 (PD-L1) expression testing is recommended by guidelines for patients with advanced non–small cell lung cancer (NSCLC). The primary objective of the current study was to determine the success rate of PD-L1 testing from cytology cell block samples obtained by bronchoscopic needle aspiration. The secondary objective was the assessment of the difference in specimen adequacy acquired via needles of different gauges. METHODS: Patients with NSCLC who underwent bronchoscopic needle aspirations for which PD-L1 testing was requested between November 1, 2016, and February 6, 2017, were included in the current analysis. Patients underwent needle aspiration from intrathoracic adenopathy or a pulmonary lesion. Rapid on-site cytology evaluation was performed in all cases. PD-L1 immunohistochemistry was performed using the Abcam anti-PD-L1 antibody 28.8 clone on cell block specimen. RESULTS: A total of 22 patients had PD-L1 testing requested on needle cytology samples obtained via bronchoscopy at the time of initial diagnosis (81.8%) and for progression of disease (18.2%). Twenty patients (90.9%) underwent successful PD-L1 testing. Sample acquisition was via endobronchial ultrasound-guided transbronchial needle aspiration in 72.7% of patients, endobronchial needle aspiration in 18.2% of patients, and peripheral nodule needle aspiration in 9.1% of patients. There was no statistical difference in PD-L1 test success rates between sample methods (P =.99) or needle sizes (P = 1.00). CONCLUSIONS: Bronchoscopically obtained cytology needle–based samples are adequate for PD-L1 testing in patients with NSCLC. There was no difference noted between different needle sizes with regard to adequacy for PD-L1 testing. These findings are relevant for clinicians caring for patients with lung cancer because a vast majority of patients with advanced NSCLC are diagnosed by bronchoscopic needle-based techniques using a variety of commercially available needles. Cancer Cytopathol 2018;126:122-8. © 2017 American Cancer Society.