The Role of Pre-operative MRI For Prediction of High-Grade Intracranial Meningioma: A Retrospective Study

Introduction: High histological grade (WHO grade II and III) intracranial meningiomas have been linked to greater risk for tumor recurrence and worse clinical outcomes compared to low-grade (WHO grade I) tumors. Preoperative magnetic resonance imaging (MRI) plays a crucial role tumor evaluation prior to decisions regarding management and allows for a better understanding of the tumor grading, which could potentially alter clinical outcomes. The present study sought to determine whether preoperative MRI features of intracranial meningiomas can serve as predictors of high-grade tumors.Methods: This study retrospectively reviewed 327 confirmed cases of intracranial meningiomas, among whom 210 (64.2%) had available preoperative MRI studies. Thereafter, data were analyzed using univariate and multivariate analyses.Results: Accordingly, multivariate analysis found that peritumoral brain edema and the presence of necrosis or hemorrhage were predictors of high-grade tumors, whereas hyperostosis was a predictor of low-grade tumors.Conclusions: Our study suggested that preoperative MRI features could potentially assist in decision-making regarding the appropriate management and surgical approach in order to achieve the desired clinical outcomes.

The Most Significant Surgical Risk Factors of Giant Intracranial Meningiomas: Localization Matters Much More than Grading and Volume of Peritumoral Brain Edema. A Retrospective Clinical Neuroradiological and Immunohistochemical Study

Background: Giant intracranial meningiomas (GIMs) are extremely rare and are usually considered arduous to resect totally with poorer prognosis. The real mechanisms by which a meningioma can grow to be defined as "giant" are unknown, as well as the real biological , radiological profile and the different outcomes.Methods: We performed a retrospective review of a consecutive series of surgically-treated patients suffering from intracranial Meningioma. All the patients were assigned on the ground of the preoperative imaging to the Giant and Medium/Large Meningiomas. We investigated whether the presence large diameter on radiological diagnosis is indicative for different mortality rate, grading, characteristic and clinical/neurological outcome.Results: The study shows that surgically treated giant meningiomas have a higher risk of developing complications in the postoperative phase (Chi square= 11.121, dF=1, p=0.001). The direct proportional relationship between peritumoral brain edema (PBE) volume and tumor volume was present only in the medium/large group and was not present in the giant meningioma group. When comparing the degree of performance there is a statistically significant difference between localization and KPS immediately postoperatively (p=0.04) particularly for sphenopetroclival meningiomas (p=0.071), and partially with GIM of the olfactory groove with arterial encasement. The most frequently encountered complications include the occurrence of ischemia (p=0.049), infection (p=0.03), and the occurrence of postoperative seizures.Conclusions: We identified that the major surgical risk factor for GIMs is location, where the petro-clival region and, to a lesser extent the anterior basicranium offer a greater risk of neurovascular involvement and arterial encasement. On other hand, the risk correlated with PBE is poorer in GIM although there is a well-noted correlation between the Edema volume and outcome in meningiomas.

Are there predilection sites for intracranial meningioma? A population-based atlas

Meningioma is the most common benign intracranial tumor and is believed to arise from arachnoid cap cells of arachnoid granulations. We sought to develop a population-based atlas from pre-treatment MRIs to explore the distribution of intracranial meningiomas and to explore risk factors for development of intracranial meningiomas in different locations. All adults (≥ 18 years old) diagnosed with intracranial meningiomas and referred to the department of neurosurgery from a defined catchment region between 2006 and 2015 were eligible for inclusion. Pre-treatment T1 contrast-enhanced MRI-weighted brain scans were used for semi-automated tumor segmentation to develop the meningioma atlas. Patient variables used in the statistical analyses included age, gender, tumor locations, WHO grade and tumor volume. A total of 602 patients with intracranial meningiomas were identified for the development of the brain tumor atlas from a wide and defined catchment region. The spatial distribution of meningioma within the brain is not uniform, and there were more tumors in the frontal region, especially parasagittally, along the anterior part of the falx, and on the skull base of the frontal and middle cranial fossa. More than 2/3 meningioma patients were females (p < 0.001) who also were more likely to have multiple meningiomas (p < 0.01), while men more often have supratentorial meningiomas (p < 0.01). Tumor location was not associated with age or WHO grade. The distribution of meningioma exhibits an anterior to posterior gradient in the brain. Distribution of meningiomas in the general population is not dependent on histopathological WHO grade, but may be gender-related.

Hypofractionated Stereotactic Radiotherapy for the Treatment of Benign Intracranial Meningiomas: Long-Term Safety and Efficacy

Introduction: Hypofractionated stereotactic radiotherapy (hSRT) has emerged as an alternative to single-fraction stereotactic radiosurgery (SRS) and conventionally fractionated radiotherapy for the treatment of intracranial meningiomas (ICMs). However, there is a need for data showing long-term efficacy and complication rates, particularly for larger tumors in sensitive locations. Methods: A retrospective review was conducted on adult patients with ICMs seen at a tertiary care center. Eligible patients were treated with the CyberKnife platform and had a planned treatment course of 3–5 fractions from 2011–2020. The local control was assessed based on radiographic stability and the late toxicity/radionecrosis rates were recorded. Radiographic progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan–Meier method. Results: In total, 62 patients (age 26–87) with 67 treated tumors were included in this study with a median follow-up of 64.7 months. RT was delivered as the primary treatment in 62.7% of cases and for recurrence in 37.3%. The most common tumor locations were the convexity of the brain and the base of the skull. The tumor sizes ranged from 0.1–51.8 cc and the median planning target volume was 4.9 cc. The most common treatment schedule was 18 Gy in 3 fractions. The five-year PFS and OS were 85.2% and 91.0%, respectively. The late grade III/IV toxicity rate was 3.2% and the radionecrosis rate was 4.8%. Conclusions: Based on our data, hSRT remains an effective modality to treat low-grade ICMs with acceptable long-term toxicity and radionecrosis rates. hSRT should be offered to patients who are not ideal candidates for SRS while preserving the benefits of hypofractionation.