Prognostic and predictive value of systemic inflammatory markers in patients with metastatic gastric and GEJ adenocarcinoma with PD-L1 CPS score ≥ 5: Turkish Oncology Group (TOG) study.

Our understanding of prognostic and predictive factors in the context of nivolumab combined with chemotherapy remains limited. In our multicenter study conducted across 16 centers, data from 153 patients with metastatic gastric adenocarcinoma and a PD-L1 CPS score ≥ 5, who received nivolumab in combination with chemotherapy as first-line treatment, were retrospectively analyzed for the period between 2021 and 2024. The study aimed to investigate the prognostic and predictive significance of neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), Systemic Immune-Inflammation Index (SII), as well as various clinical parameters. The estimated median progression-free survival (PFS) was 11.06 months while the estimated median overall survival (OS) was 16.03 months. Patients who were initially diagnosed with metastatic disease had a significantly worse prognosis, as was those with lung metastases. Lower NLR, PLR, and SII values were associated with longer PFS and OS in the univariate analysis; however, their statistical significance was not mantained in the multivariate analysis. SII and PD-L1 CPS score were determined as independent predictive factors for nivolumab plus chemotherapy treatment response. Our study is the only one to date that sheds light on prognostic and predictive factors in patients with metastatic gastric or GEJ adenocarcinoma and a PD-L1 CPS score ≥ 5, who received nivolumab in combination with chemotherapy.