Gustave Roussy Immune (GRIm) score as a novel prognostic biomarker for gastrointestinal cancers: a meta-analysis of sixteen studies

The Gustave Roussy immune (GRIm) score has been widely recognized as a promising prognostic biomarker in various malignancies. This study aimed to systematically evaluate the association between pretreatment GRIm score and survival outcomes in patients with gastrointestinal (GI) cancers. A systematic literature search was conducted using electronic databases (Web of Science, PubMed, Cochrane Library and Embase) from inception to January 15, 2026. The primary endpoints included long-term survival outcomes such as overall survival (OS), disease-free survival (DFS), recurrence-free survival (RFS), progression-free survival (PFS), and cancer-specific survival (CSS). Pooled hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using a random-effects model. The meta-analysis was prospectively registered with PROSPERO (CRD420261291292). This meta-analysis included 16 studies comprising 4,904 patients with GI cancers. The pooled outcomes demonstrated that patients with a high GRIm score had significantly worse OS (15 studies; HR = 2.01; 95% CI: 1.69–2.40; P < 0.01; I² = 63%), PFS (8 studies; HR = 1.57; 95% CI: 1.29–1.91; P < 0.01; I² = 48%), DFS (2 studies; HR = 2.15; 95% CI: 1.35–3.42; P < 0.01; I² = 55%) and CSS (2 studies; HR = 1.68; 95% CI: 1.17–2.41; P < 0.01; I² = 4%) compared to those with a low score. However, a single study assessing RFS reported that the GRIm score lacked independent prognostic significance for this endpoint (HR = 1.69; 95% CI: 0.77–3.73; P = 0.19). Our findings suggest that the pretreatment GRIm score may serve as a prognostic biomarker in patients with GI cancers. However, further high-quality studies are required to robustly validate its prognostic utility.