This study evaluated the ability for pretreatment peripheral immune cell ratios (Neutrophil-to-Lymphocyte Ratio, NLR, and Monocyte-to-Lymphocyte Ratio, MLR) to predict overall survival (OS) and modified Rankin Scale (mRS) at admission, 6 months and 12 months post-diagnosis. It also explored relationships between immune cell ratios and clinicopathological parameters (tumour location, tumour size, tumour grade, IDH-1 mutation and MGMT promoter methylation status).

In the glioma microenvironment, elevations in immune cell ratios are posited to reflect host systemic response to malignancy. Given the dearth in clinically significant molecular markers to predict prognosis, there is potential for immune cell ratios to serve as low-cost and readily available prognostic markers.

Pretreatment NLR and MLR were analysed retrospectively in 64 glioma patients from Royal Melbourne Hospital. Receiver-operating characteristic analyses were used to determine NLR and MLR cut-off values. OS was evaluated with the Kaplan-meier method. Prognostic factors for OS and mRS were evaluated with cox hazard regression analyses and binary logistic regression analyses respectively.

Higher pretreatment NLR (>4.7), compared to lower pretreatment NLR (≤ 4.7), predicted higher mean admission mRS (mean 3.31 vs 2.40, p<0.001) and 6-month mRS (mean 3.60 vs 2.44, p=0.019). Higher pretreatment NLR was associated with poor functional outcome (mRS 3-6) at admission (p<0.001) and 6 months (p=0.001). Higher pretreatment MLR (>0.35) predicted poorer OS in glioma patients (median 57.0 ± 6.6 weeks, 95% CI 43.4-70.6, p=0.024). Higher NLR was associated with larger tumour diameter (≥5cm) (p=0.02).

To our knowledge, this was the first study to evaluate the association between immune cell ratios and mRS in glioma patients. It demonstrated that NLR and MLR can serve as prognostic markers to predict functional outcomes and OS in glioma patients. These findings allow us to identify high-risk patients in need of further treatment and advance understanding of the role of immune cells in glioma pathogenesis.