Locally advanced non-small cell lung cancer with negative or low programmed death ligand 1 expression: a prognostic factor analysis of real-world data after the PACIFIC trial.

BACKGROUND: Real-world data on patients with locally advanced non-small cell lung cancer (LA-NSCLC) treated with chemoradiotherapy have been reported; however, prognostic factors in patients with negative or low programmed cell death ligand 1 (PD-L1) expression are unclear. Therefore, we aimed to explore prognostic factors in patients with LA-NSCLC with negative or low PD-L1 expression using real-world data obtained after the PACIFIC trial. METHODS: Patients with LA-NSCLC with negative or low PD-L1 expression who received definitive radiotherapy at our institution between March 2017 and May 2022 were included. Competing risk analyses were used to evaluate cumulative incidence of cancer-specific death (CI-CSD), cumulative incidence of recurrence (CI-R), cumulative incidence of distant metastasis (CI-DM), and cumulative incidence of in-field recurrence (CI-IFR). RESULTS: The study included the data of 130 patients. Median follow-up was 37 (range, 2–72) months after radiotherapy initiation; 54 (41.5%) patients died, among whom 49 died of lung cancer, and 75 (57.7%) received durvalumab. Multivariate analyses revealed that interstitial lung abnormality (ILA) score ≥ 1 was a significant factor of shorter OS and higher CI-IFR, and a mean heart dose ≥ 7.5 Gy showed a trend toward significance for shorter OS., Internal high-dose volumetric modulated arc therapy was associated with lower CI-R, whereas poor baseline performance status correlated with higher CI-DM. Notably, durvalumab administration was marginally associated with lower CI-R. CONCLUSIONS: Pre-treatment ILA and high mean heart doses negatively impacted OS in patients with LA-NSCLC with negative or low PD-L1 expression according to real-world data obtained after the PACIFIC trial.