Inclusion Criteria:

          1. Age at diagnosis, at least 3 - 5 years (depending on the country) and less than 22
             years (LR-arm: less than 16 years). The date of diagnosis is the date on which surgery
             is undertaken.

          2. Histologically proven medulloblastoma, including the following subtypes, as defined in
             the WHO classification (2007): classic medulloblastoma, desmoplastic/nodular
             medulloblastoma. Pre-treatment central pathology review is considered mandatory.

          3. Standard-risk medulloblastoma, defined as;

               -  total or near total surgical resection with less than or equal to 1.5 cm2
                  (measured on axial plane) of residual tumour on early post-operative MRI, without
                  and with contrast, on central review;

               -  no central nervous system (CNS) metastasis on MRI (cranial and spinal) on central
                  review;

               -  no tumour cells on the cytospin of lumbar CSF

               -  no clinical evidence of extra-CNS metastasis; Patients with a reduction of
                  postoperative residual tumor through second surgery to less than or equal to 1.5
                  cm2 are eligible, if if timeline for start of radiotherapy can be kept.

          4. Submission of high quality biological material including fresh frozen tumor samples
             for the molecular assessment of biological markers (such as the assessment of
             myelocytomatosis oncogene (MYC) copy number status) in national biological reference
             centers. Submission of blood is mandatory for all patients, who agree on germline DNA
             studies. Submission of CSF is recommended.

          5. No amplification of MYC or MYCN (determined by FISH).

          6. For LR-arm: Low-risk biological profile, defined as WNT subgroup positivity. The WNT
             subgroup is defined by the presence of (i) ß-catenin mutation (mandatory testing), or
             (ii) ß-catenin nuclear immuno-positivity by IHC (mandatory testing) and ß-catenin
             mutation, or (iii) ß-catenin nuclear immuno-positivity by IHC and monosomy 6 (optional
             testing).

             For SR-arm: average-risk biological profile, defined as ß-catenin nuclear
             immuno-negativity by IHC (mandatory) and mutation analysis (optional).

          7. No prior therapy for medulloblastoma other than surgery.

          8. Radiotherapy aiming to start no more than 28 days after surgery. Foreseeable inability
             to start radiotherapy within 40 days after surgery renders patients ineligible for the
             study.

          9. Screening for the compliance with eligibility criteria should be completed, and
             patient should be included into the study within 28 days after first surgery (in case
             of second surgery within 35 days after first surgery). Inclusion of patients is not
             possible later than 40 days after first tumour surgery, or after start of
             radiotherapy.

         10. Common toxicity criteria (CTC) grades < 2 for liver, renal, haematological function

         11. no significant sensorineural hearing deficit as defined by pure tone audiometry with
             bone conduction or air conduction and normal tympanogram showing no impairment ≥ 20
             decibel (dB) at 1-3 kilohertz (kHz). If performance of pure tone audiometry is not
             possible postoperatively, normal otoacoustic emissions are acceptable, if there is no
             history for hearing deficit.

         12. No medical contraindication to radiotherapy or chemotherapy, such as preexisting DNA
             breakage syndromes (e.g. Fanconi Anemia, Nijmegen breakage syndrome), Gorlin Syndrome
             or other reasons as defined by patient's clinician.

         13. No identified Turcot and Li Fraumeni syndrome.

         14. Written informed consent (and patient assent where appropriate) for therapy according
             to the laws of each participating country. Information must be provided to the patient
             on biological studies (tumour and germline), and written informed consent obtained of
             agreement for participation.

         15. National and local ethical committee approval according to the laws of each
             participating country (to include approval for biological studies).

        Exclusion Criteria:

          1. One of the inclusion criteria is lacking.

          2. Brainstem or supratentorial primitive neuro-ectodermal tumour.

          3. Atypical teratoid rhabdoid tumour.

          4. Medulloepithelioma; Ependymoblastoma

          5. Large-cell medulloblastoma, anaplastic medulloblastoma, or medulloblastoma with
             extensive nodularity (MBEN), centrally confirmed.

          6. Unfavourable or undeterminable biological profile, defined as amplification of MYC or
             MYCN, or MYC or MYCN or WNT subgroup status not determinable.

          7. Metastatic medulloblastoma (on CNS MRI and/or positive cytospin of postoperative
             lumbar CSF).

          8. Patient previously treated for a brain tumour or any type of malignant disease.

          9. DNA breakage syndromes (e.g. Fanconi anemia, Nijmegen breakage syndrome) or other, or
             identified Gorlin,Turcot, or Li Fraumeni syndrome.

         10. Patients who are pregnant.

         11. Female patients who are sexually active and not taking reliable contraception.

         12. Patients who cannot be regularly followed up due to psychological, social, familial or
             geographic reasons.

         13. Patients in whom non-compliance with toxicity management guidelines can be expected.