Diagnostic yield of endobronchial ultrasound-guided transbronchial needle aspiration to assess tumor-programmed cell death ligand-1 expression in mediastinal lymph nodes metastasized from non-small cell lung cancer.

Abstract

We investigated the utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) to evaluate programmed cell death ligand-1 (PD-L1) expression in patients with advanced non-small cell lung cancer (NSCLC). A retrospective chart review of patients who underwent EBUS-TBNA between April 2017 and April 2019 was conducted. Among patients diagnosed with NSCLC, we investigated the rate of successful evaluation of tumor PD-L1 expression, compared the relevant factors between patients with evaluable and those with unevaluable PD-L1 expression, and examined the response to immune checkpoint inhibitors (ICIs) after EBUS-TBNA. Of the 40 patients assessed, 32 (80%) had evaluable PD-L1 expression. Patients with evaluable PD-L1 expression were older than those with unevaluable PD-L1 expression (p = 0.017), and we noted a tendency for a larger diameter of the biopsied lymph node (p = 0.12). The response rate to ICIs was 100% in patients with a tumor proportion score (TPS) ≥ 50%, 33% in those with a TPS 1-49%, and 0% in those with a TPS < 1%. The diagnostic yield of EBUS-TBNA to evaluate PD-L1 expression in advanced NSCLC appeared acceptable in association with relevant clinical outcomes after treatment with ICIs. A further prospective study with a larger sample size is required to confirm our findings.