Navigational bronchoscopy specimens and PD-L1 expression: a retrospective study.

Background: Additional data regarding the ability of navigational bronchoscopy (NB) to provide sufficient material for programmed death-ligand 1 (PD-L1) expression is needed. We performed a retrospective study of NB cases at our institution to determine performance of NB in providing adequate samples for PD-L1.

Methods: We conducted a retrospective review of all consecutive NB procedures performed at our institution from January 1, 2018 to August 4, 2020 that involved biopsies of a lung nodule/mass with a diagnosis of non-small cell lung cancer (NSCLC). The primary outcome was adequacy of material for PD-L1 testing. All procedural, demographic, and diagnostic data were collected. The association of factors with PD-L1 adequacy was evaluated with rate ratios (RR) using modified Poisson regression models with robust standard errors.

Results: A total of 102 NB procedures with a diagnosis of NSCLC were performed over a 2-year period. The mean [standard deviation (SD)] nodule size was 25.0 [interquartile range (IQR), 18.0-32.0] mm and 57.8% (59/102) had a bronchus sign; 73% (68/93, 9 missing data) of samples were adequate for PD-L1 testing. Radial endobronchial ultrasound (REBUS) was utilized in 99% (101/102) of biopsies; a concentric or eccentric view was observed in 78.2% (79/101) and 16.8% (17/101), respectively. Transbronchial biopsy (TBBX) was performed in 92.2% (94/102). Only 4% (4/102) of cases required additional biopsies with either computed tomography (CT) guided transthoracic or surgical biopsies due to insufficient bronchoscopy tissue. No factors were predictive of PD-L1 adequacy in regression models.

Conclusions: NB demonstrated good performance in obtaining adequate samples for PD-L1 testing. Only 4% of patients required additional procedures for more tissue when clinically indicated. However, additional study is needed to validate these results against surgical resection specimens.