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

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 2017. © 2017 American Cancer Society.

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