Long-term Cognitive and Functional Impact of Proton-therapy or Modern Fractionated Radiotherapy in Cavernous Sinus Meningioma: An Open-label Randomized 1:1 Phase III Study

Inclusion Criteria: * Cavernous sinus meningioma for which clinical target volume is larger than 3 centimeters * Anterior skull base meningioma, invading by contiguity the cavernous sinus can be included * Histologic proven Grade I meningioma * Meningioma for which biopsy is not safely achievable and for which growing and imaging criteria are in favour of grade I meningioma can be included * Age \>18 years and ≤70 years * Indication of irradiation validated by a pluridisciplinary meeting * Adjuvant or exclusive irradiation is allowed. * Use of conventional fractionation: 1.8Gy (RBE)/fraction * Signed informed consent form * WHO Performance status equal to 0 or 1 * Patient affiliated to the French social health insurance * MoCA score ≥ cut-off of GRECOGVASC normative data (Roussel, 2016, cf annexe 1) * Patient whose neuropsychological abilities allow to follow the requirements of the protocol Exclusion Criteria: * Patient with mutation in a known predisposition gene (NF-2, SMARCE-1…) * Cerebrovascular pathology, presence of other tumors of the nervous system, congenital malformations of the nervous system, multiple sclerosis, Parkinson's disease and other dementias, organic psychosis (other than dementia), schizophrenia, and neurodegenerative disease * Radiosurgery, hypofractionated regimen * Other localization than cavernous sinus * Histologic proven Grade II or III meningioma * Patient with unadjusted antiepileptic drug * Contraindication to MRI * Patient with a history of brain irradiation * Patient with a history of cancer in the last five years (excluding skin baso-cellular carcinoma) * Pregnant/breastfeeding woman * Any geographical conditions, social and associated psychopathology that may compromise the patient's ability to participate in the study * Participation in a therapeutic trial for less than 30 days * Patient deprived of freedom or under guardianship