SuperDEX Trial (Comparison of Two Doses of Dexamethasone for Malignant Spinal Cord Compression Treated by Radiotherapy).

Inclusion Criteria: * Malignant spinal cord compression with at least one of pain, weakness, sensory disturbance or sphincter disturbance * Histology not required if prior biopsy proven malignancy * Any stage * Age \>16 years * ECOG 1-3 prior to cord compression event * Minimum power 1 of 5 point scale Must not be paraplegic * Minimum expected survival 2 months * Relevant minimum lab values * Patients capable of childbearing using adequate contraception * Written informed consent Exclusion Criteria: * Prior radiotherapy to within vertebral±one level affected by cord compression * Prior treatment for spinal cord compression at the current level * Histology is lymphoma or myeloma * Power less than 1 of 5 * More than 12 hours after initiation of dexamethasone\>4mg/24hr * Pre-existing co-morbid conditions - peptic ulceration or cardiac failure * Allergy to study medications * Multilevel cord compression or meningeal carcinomatosis * Pregnant or lactating