Prognostic value of inflammatory markers in glioblastoma: A meta-analysis of NLR and PLR stratified by cutoff values.

2067 Background: Glioblastoma (GBM) is the most aggressive primary brain tumor in adults, with an unfavorable prognosis. Identifying prognostic markers is crucial to stratify patients and tailor therapeutic approaches. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are inflammatory markers that have gained attention as outcome predictors in various cancers. While numerous studies have demonstrated associations between elevated NLR, PLR, and poor GBM outcomes, consensus on standardized cutoff values remains elusive, limiting their clinical application. In this meta-analysis, we stratified the data based on preoperative NLR and PLR cutoff values, aiming to identify the most accurate cutoff thresholds to predict overall survival (OS) outcomes. Methods: We performed a systematic search on PubMed, Medline, OVID, Embase, and Cochrane in November 2024 to identify cohort studies reporting hazard ratios (HR) for OS associated with preoperative NLR and/or PLR in patients with histopathologically confirmed GBM. Two reviewers screened articles; discrepancies were resolved by consensus. Data analysis was conducted using a random-effects model. Pooled HRs with 95% confidence intervals (CI) were calculated and subgroup analysis were performed. Results: From 227 studies initially identified, 22 studies met our inclusion criteria, encompassing a total population of 3,423 patients with GBM. In our general cohort, when compared to lower PLR, a higher PLR yielded a pooled HR of 1.30 (95% CI: 1.12-1.50, p < 0.001). Specific cutoff subgroup analysis revealed that, the < 135 cutoff group had a HR of 1.09 (95% CI: 0.62-1.93, p = 0.60), in the > 135 cutoff group, the HR was 1.42 (95% CI: 1.19-1.70, p = 0.0001). Regarding the NLR analysis, cutoff subgroup analysis showed that for NLR with a cutoff of < 3, the HR was 1.39 (95% CI: 0.96–2.02, p = 0.08), for NLR with a cutoff between 3 and 4.9, the HR was 1.56 (95% CI: 0.98–2.51, p = 0.06). For studies with a NLR cutoff of 4, the HR was 1.40 (95% CI: 1.23–1.58, p = 0.01). For studies with a NLR cutoff > 4.9, the HR was 1.85 (95% CI: 1.37–2.50, p < 0.0001). The overall pooled HR for elevated NLR regardless of cutoff value was 1.40 (95% CI: 1.23–1.58, p < 0.00001). Conclusions: Elevated preoperative NLR and PLR are significant prognostic markers for worse OS in GBM patients. Stratifying data by cutoff values revealed that PLR > 135 and NLR > 4.9 were more consistently correlated with poor survival outcomes. These findings suggest that higher cutoff values for these markers may better predict OS, particularly for NLR where values > 4.9 demonstrated a stronger association than the commonly used cutoff of 4. The results highlight the potential utility of NLR and PLR as accessible, cost-effective prognostic tools. Future prospective studies are warranted to validate these findings, refine optimal cutoff thresholds, and explore their applicability.