Brain tumors are the second most frequent malignant diseases in children and adolescents. In the study the short and medium term consequences of proton therapy on cognitive processes in particular on executive functions in pediatric patients shall be highlighted/analysed/evalutated. In a second step, these results are to be compared with

1. a group of children and adolescents who had only /exclusively had operative therapy and
2. with a healthy control group. Thus, the extent to which these treatment options differ in terms of their short and medium-term effect is assessed. Methods of neurocognitive/neurophysiology brain research approaches are applied that may potentially visualize even small / subtle changes in mental activities/neurocognitive function. Therefore the effects of treatment can be evaluated and the neuropsychological outcome of children and adolescents with brain tumors can be improved.

Radio(chemo)therapy with protons is conducted according to current treatment standards or, for patients participating in a clinical intervention study, according to the study protocols of the GPOH. Only patients with prescribed radiation doses > 40 Gy (RBE) will be included. Treatment planning, the target volume and radiotherapy will be performed according to the current treatment standards. For patients participating in a clinical intervention study, radiotherapy is corresponding to study protocol of the GPOH. Risk organs (e.g. brain stem, chiasma, optic nerves, gll. Lacrimals, lenses, inner ears and spine) are contoured and the radiation doses for these organs are limited according to institutional guidelines. Radiotherapy is performed according to guidelines, i.e. 5 days a week for 4-6 weeks, usually on an outpatient basis.

Indication: Patients with primary brain tumor

Inclusion Criteria:

• all groups: Patients in childhood and adolescence between 8-18 years of age
• all groups: no prior radiotherapy of the brain,
• all groups: The patient is able to perform repeated neuropsychological tests (approx. 1 hour per examination),
• all groups: corrected visual acuity not impaired below 80% or no subjective indication of visual acuity impairment,
• all groups: corrected hearing not impaired or no subjective evidence of hearing impairment,
• all groups: Patient is able to perform follow-up examinations,
• all groups: written consent of the patient/parent or guardian.
• Brain tumour groups with/without irradiation: Primary brain tumour
• brain tumor groups with/without radiation: curative or long-term palliative intention of therapy
• brain tumor groups with/without irradiation: life expectancy > 3 years
• Irradiation group only: planned proton therapy with a local radiation dose of at least 40 Gy(RBE)

Exclusion Criteria:

• Patients under 8 or over 18 years of age (We limit the study to children over 8 years of age due to the fact that executive functions mature very late.)
• Brain metastases from extracerebral tumors
• Patient receives intrathecal chemotherapy
• pure palliative treatment concept
• The patient is not able to perform repeated neuropsychological tests (approx. 1 hour per examination).
• Chronic diseases that may affect the results of neurological EEG and neuropsychological examinations.
• The patient is not in a position to perform follow-up examinations
• no written consent of the patient / parent or legal guardian
• Participation in an intervention study whose procedures contradict those of the present study

30 patients with infra-tentorial or supra-tentorial tumors undergoing proton therapy, 30 patients undergoing surgical treatment and a control cohort of 30 adolescents. Therefore, a total of 90 persons will be evaluated.