Diffuse low-grade gliomas are highly epileptogenic brain tumours. We aimed to explore the natural course of epileptic seizures, their predictors and the prognostic significance of their occurrence in adult patients harbouring a diffuse low-grade glioma. An observational retrospective multicentre study examined 1509 patients with diffuse low-grade gliomas to identify mutual interactions between tumour characteristics, tumour course and epileptic seizures. At diagnosis, 89.9% of patients had epileptic seizures. Male gender (P = 0.003) and tumour location within functional areas (P = 0.001) were independent predictors of a history of epileptic seizures at diagnosis. Tumour volume, growth velocity, cortical location, histopathological subtype or molecular markers did not significantly affect epileptic seizure occurrence probability. Prolonged history of epileptic seizures (P < 0.001), insular location (P = 0.003) and tumour location close to functional areas (P = 0.038) were independent predictors of uncontrolled epileptic seizures at diagnosis. Occurrence of epileptic seizures (P < 0.001), parietal (P = 0.029) and insular (P = 0.002) locations were independent predictors of uncontrolled epileptic seizures after oncological treatment. Patient age (P < 0.001), subtotal (P = 0.007) and total (P < 0.001) resections were independent predictors of total epileptic seizure control after oncological treatment. History of epileptic seizures at diagnosis and total surgical resection were independently associated with increased malignant progression-free (P < 0.001 and P < 0.001) and overall (P < 0.001 and P = 0.016) survivals. Epileptic seizures are independently associated with diffuse low-grade glioma prognosis. Patients diagnosed with epileptic seizures and those with complete and early surgical resections have better oncological outcomes. Early and maximal surgical resection is thus required for diffuse low-grade gliomas, both for oncological and epileptological purposes.

In adults, as in children, H3 K27M mutations define a distinct subgroup of IDH wild-type gliomas characterized by a constant midline location, low rate of MGMT promoter methylation, and poor prognosis.

Meningiomas represent one of the largest subgroups of intracranial tumors. They are generally benign, but may show a histological progression to malignancy. Grades II and III meningiomas have been less well studied and are not well controlled because of their aggressive behaviour and recurrences. There is no consensus on therapeutic strategies and no prognostic factors are known. In order to determine these parameters, a multi-institutional retrospective analysis was performed in France with the support of the Neuro-Oncology Club of the French Neurosurgical Society. This study was performed on 199 adults treated for WHO grade II (166 patients) or grade III (33 patients) meningiomas between 1990 and 2004 in the Neurosurgery Departments of five French University Hospitals. Data on epidemiology, clinical behaviour and therapy were collected. Overall survival and progression-free survival were analysed as a function of each possible prognostic factor. For patients with grade II meningiomas, the 5- and 10-year OS rates were 78.4 and 53.3%, respectively, while, for patients with grade III meningiomas, the corresponding values were 44.0 and 14.2%. For patients with grade II meningiomas, the 5- and 10-year PFS rates were 48.4 and 22.6%, respectively, the corresponding values for patients with grade III meningiomas being 8.4 and 0%. For the grade II meningiomas, univariate analysis showed that age < 60 years (P < 0.0001) and Simpson 1 resection (P = 0.055) were associated with a longer OS. For the grade III meningiomas, univariate analysis showed that age < 60 years (P < 0.0001) and RT (P = 0.036) were associated with a longer OS. Histological grade II was found to be associated with a longer PFS (P = 0.0032) and RT reduced the PFS in grade II meningiomas (P = 0.0006) There were no other prognostic factors in terms of PFS for grades II and III meningiomas in univariate analysis. Multivariate analysis confirmed that age (< 60 years), Simpson 1 and histological grade II were independent prognostic factors for survival. This retrospective study might improve the management of grades II and III meningiomas. Prospective trials should delineate strong therapeutic guidelines for high-grade meningiomas.

This large series with its volumetric assessment refines the prognostic value of previously stressed clinical and radiological parameters and highlights the importance of tumor size and location. The results support additional arguments in favor of the predominant role of resection, in accordance with recently reported experiences.