Hyperfractionated Versus Conventionally Fractionated Radiotherapy in Standard Risk Medulloblastoma (PNET4)

Inclusion Criteria:

* Age at diagnosis at least 4 years or 5 years (according to the policy of the National Brain Tumour Group) and less than 22 years.
* Histologically proven medulloblastoma, including the following variants(WHO classification - 2000): classic medulloblastoma, nodular / desmoplastic medulloblastoma, melanotic medulloblastoma, medullomyoblastoma No CNS metastasis on MRI - supratentorial, arachnoid of the posterior fossa or spine.
* No clinical evidence of extra-CNS metastasis
* No tumour cells on the cytospin of lumbar CSF. Central Review of CSF cytology is recommended but not mandatory. It will be left to national policy.
* Radiotherapy to start no more than 40 days after surgery.
* Ability to receive twice daily radiotherapy.
* Vital functions within normal range for their age group.
* CTC grades \< 2 for liver, renal, haematological and audiological function.
* No medical contraindication to radiotherapy or chemotherapy.
* Written informed consent (and patient assent where appropriate) according to the laws of each participating country. Written informed consent should also be sought for biological studies.
* National and local ethical committee approval according to the laws of each participating country (to include approval for biological studies).

Exclusion Criteria:

* One of the inclusion criteria is lacking.
* Brainstem or supratentorial primitive neuroectodermal tumour.
* Atypical teratoid rhabdoid tumour.
* Medulloepithelioma.
* Ependymoblastoma.
* Large cell médulloblastoma.
* Metastatic medulloblastoma (on CNS MRI and/or positive cytospin of postoperative lumbar CSF).
* Patient previously treated for a brain tumour or any type of malignant disease.
* Patients who are pregnant.
* Females who are sexually active and not taking reliable contraception.
* Known predisposition to medulloblastoma e.g. Gorlin's syndrome.