- Karnofsky >= 50% for patients > 16 years of age and Lansky >= 50 for patients =< 16 years of age; Note: Neurologic deficits in patients with CNS tumors must have been stable for at least 7 days prior to study enrollment; patients who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score