A novel inflammation and tumor marker‑based prognostic score, neutrophil‑lymphocyte ratio‑C‑reactive protein‑Ca19‑9, in metastatic gastric cancer

Metastatic gastric cancer is an aggressive malignancy characterized by poor survival rates and heterogeneous treatment outcomes. Reliable prognostic tools to identify patients who may benefit from systemic therapy remain limited. Therefore, there is a need for easily accessible and clinically applicable prognostic tools. The present single‑center retrospective study included 70 patients with microsatellite‑stable, HER2‑negative metastatic gastric cancer who were treated with first‑line fluoropyrimidine‑based chemotherapy between 2020 and 2024. The present study aimed to develop and evaluate a novel composite prognostic score integrating systemic inflammation and tumor burden. The neutrophil‑C‑reactive protein (CRP)‑CA19‑9 (NCC) score was constructed based on baseline neutrophil‑to‑lymphocyte ratio (NLR ≥5), CRP >20 mg/l and CA19‑9 levels (>90 U/ml). Patients were classified into low‑risk (0‑1) and high‑risk (2‑3) groups. Overall survival (OS) and progression‑free survival (PFS) were analyzed using Kaplan‑Meier and Cox regression methods, with internal validation performed by bootstrap resampling. The median OS for the entire cohort was 13.4 months. A high NCC score was associated with significantly shorter OS compared with a low NCC score (9.6 vs. 15.2 months; P=0.00065) and an increased risk of mortality (hazard ratio=2.59; 95% CI: 1.47‑4.56). The median PFS was also shorter in the high‑risk NCC group (9.2 vs. 10.1 months; P=0.04). The optimism‑corrected C‑index for OS was 0.60, indicating that the NCC score is a simple and practical prognostic tool for survival stratification with favorable discriminative performance compared with established prognostic indices in metastatic gastric cancer.