Impact of Programmed Death Ligand 1 Expression on Outcomes in Stage I-II Epidermal Growth Factor Receptor-Mutant Lung...

We aimed to investigate the clinicopathological characteristics and prognostic significance of programmed death ligand 1 (PD-L1) expression in patients with pathological stage I-II epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma (LUAD) undergoing surgical resection.

Patients with EGFR-mutant LUAD who underwent complete surgical resection between 2017 and 2019 at 2 institutions were retrospectively analyzed. PD-L1 expression was assessed using the tumor proportion score (TPS) with a cutoff of ≥ 1%. Clinical outcomes, including recurrence-free survival (RFS) and overall survival, were examined based on PD-L1 expression. Propensity score matching was used to reduce confounding, and multivariate analyses were performed to identify independent prognostic factors. Additionally, progression-free survival (PFS) was assessed based on PD-L1 expression to investigate the efficacy of EGFR-tyrosine kinase inhibitors (EGFR-TKIs) after postoperative recurrence.

Among 243 patients identified, those classified as PD-L1-positive (TPS ≥ 1%) exhibited significantly shorter 5-year RFS than PD-L1-negative patients (81.3% vs. 95.3%, P < .001). Male sex, advanced pathological T factor, tumor differentiation, and visceral pleural invasion or lymphovascular invasion were identified as significant predictors of recurrence. Although the population was small, the PFS for PD-L1-positive patients who received EGFR-TKIs was 21.4 months, which was significantly longer than the 7.6 months for PD-L1-negative patients.

PD-L1 expression is a useful biomarker for predicting postoperative recurrence in patients with EGFR-mutant LUAD, and the therapeutic effect of EGFR-TKIs is sufficient even in PD-L1-positive patients. These findings support the current treatment guidelines and highlight the need for further studies to explore the role of PD-L1 in postoperative management.