Meningioma are slow growing and frequently occurring intracranial tumors, responsible for 33% of all asymptomatic intracranial tumors and 13-26% of all symptomatic primary brain tumors. The 10-year survival rate is 72%. A variety of treatment options is available for symptomatic meningioma including surgical removal with or without radiotherapy or radiotherapy alone. These therapies can have negative impact on cerebral functioning.

After high dose radiotherapy for primary or metastatic brain tumors 50-90% of > 6 months' survivors develop irreversible disabling cognitive decline leading to premature loss of independence, reduced Quality of Life (QOL) as well as significant economic burden both at the individual as societal level. Especially for patients with a good prognosis like benign meningioma, maintaining neurocognitive function is crucial. Understanding the mechanisms underlying radiation induced cognitive decline is complex and which brain areas to spare are an important subject of research.

Evaluation methods to assess cognitive function and predict cognitive decline are urgently needed, this will allow the development of optimized treatment strategies with the aim to preserve or even improve cognitive function in meningioma patients. Improvements in the field of neuroimaging techniques (i.e. advanced MRI techniques) have the possibility to identify areas susceptible to cognitive impairment. This allows in the future a more personalized radiation treatment by identifying patients at risk, by optimizing the radiotherapy dose to specific brain regions, that could eventually reduce or prevent, cognitive decline. Improvements in the field of radiotherapy for example by higher precision treatment such proton therapy have potential in obtaining these more individualized strategies.

Inclusion Criteria:

• Meningioma WHO I, grading based on pathology or radiological features
• Age ≥ 18 years.
• Karnofsky Performance Score 70 or above.
• Ability to comply with the protocol, including neuropsychological testing and imaging.
• Ability to understand the requirements of the study and to give written informed consent, as determined by the treating physician.
• Written informed consent.

Exclusion Criteria:

• Resection meningioma < 3mnd
• Age < 18 years
• Pregnancy
• Any prior cranial radiotherapy
• Any prior chemotherapy in the last 5 years
• Contra-indication for MR imaging (i.e. metal implants, claustrophobia)
• Any other serious medical condition that could interfere with follow-up.
• Severe aphasia or language barrier interfering with assessing endpoints (i.e. completion of questionnaires or neurocognitive performance)

Adult (18 years or older) patients with meningioma tumours (WHO I) in a good clinical condition treated with curative intend using radiotherapy (proton or photon) without other known malignancies.