Increased preoperative levels of circulating erythrocytic hemoglobin are independent predictors for high-grade histology (WHO 2-3) in falcine and parasagittal meningiomas

Background. Falcine/parasagittal lesions stand out among other intracranial meningiomas for their extreme histological heterogeneity, accounting for the highest rate of high-grade lesions. The ability to preoperatively estimate the lesion’s grade and clinical outcome would be of great value in orienting and customizing the treatment approach. Currently, no validated clinical/radiological predictive factors for tumoral grade and prognosis are available. Methods. This is a single-center, retrospective study designed to assess pre-operative peripheral blood markers' diagnostic/prognostic role in patients harboring falcine (FM) and parasagittal (PM) high-grade meningiomas. N=116 patients undergoing surgical resection for single FM/PM lesions were included. A propensity score-matched analysis has been performed to account for gender imbalances in low-grade (LG) vs high-grade (HG) cohorts. Results. Seventy-three (n=73) FM (63%), and 43 PM (37%) lesions were included. Median volume was 31.1 cm3 (IQR 17.1-65.4). The LG cohort comprised n=73 WHO grade 1, whereas the HG included n=34 grade 2 (29.4%), and n=9 grade 3 tumors (7.8%). Patients harboring HG lesions showed significantly higher baseline Hb levels than LG (mean 14.5 ± 1.40 vs 13.5 ± 1.16 g/dl, p<0.001). Multivariate analysis controlling for demographics, lesional characteristics, blood markers, and steroid dose, confirmed preoperative Hb as an independent predictive value of lesional grade (OR 1.76, 95% CI: 1.01-3.08, p=0.04). Accordingly, patients showing increased Hb levels >15.4 g/dl achieved shorter OS (60.4 months, 95% CI: 14.7-106.1 vs 134.7 months, 95% CI: 111.2-158.2) compared to patients with lower Hb values, p < 0.001. Data were confirmed in propensity score-matched cohorts accounting for gender imbalances among LG/HG. Conclusions. Despite the intrinsic inter-individual and time-dependent variability of blood markers, increased circulating erythrocytic hemoglobin might be independent predictors for high-grade meningioma histology, correlating with shorter overall survival in falcine and parasagittal meningiomas. Further, larger, studies are needed to validate this association and explore its potential clinical meaning and role.