Low Dose Versus Usual Dose Dexamethasone for Symptom Control in Children Undergoing Cranial or Craniospinal Radiation

Inclusion Criteria for Enrolment:

* Children between 2-18 years of age.
* Children who underwent resection of a brain tumour with ≤ 1.5 cm2 residual tumour after surgical resection.
* Children regardless of extent of leptomeningeal or spinal metastasis (M1-3) are eligible.
* Children who undergo focal or whole brain (± spinal) radiation as part of their brain tumour treatment.
* Children treated at one of the 16 tertiary care centers in Canada (CPBTC).
* Patients on any anticonvulsive treatment are eligible.
* Patients on concomitant chemotherapy while undergoing radiation are eligible.
* Patients must be ≥ 24 hours steroid-free prior to starting radiation.
* Parents/legal guardians have to have signed and dated an informed consent to allow study enrolment of their child. (As per institutional guidelines, patients over a certain age may have signed their own informed consent form.)
* Patients \> 8 years of age should assent to study participation.
* Patients less than 10 years of age should have a Lansky Score of \>/= 50.
* Patients 10 years of age or older should have a Karnofsky Score of \>/= 50. If ECOG performance scale is used, patient should have a score of 0, 1 or 2.

Exclusion Criteria for Enrolment:

* Children with residual brain tumour lesion \> 1.5 cm2 after surgical resection.
* Children on steroids (dexamethasone) that will not be stopped ≥ 24 hours prior to start of radiation therapy.

Inclusion Criteria for Randomization to a Dexamethasone treatment group:

* Patients must have been enrolled on the Dexamethasone study prior to the start of radiation therapy.
* Children who develop either symptoms of vomiting (defined as either retching or vomiting ≥ once per day) or headache (≥ 2 points increase in severity of the most intense headache/day) while undergoing irradiation.
* Patients who are currently undergoing focal or whole brain (± spinal) radiation.

Exclusion Criteria for Randomization to a Dexamethasone treatment group:

* Patients who were not enrolled on Dexamethasone study prior to start of radiation therapy.