- Performance Level: Karnofsky greater than or equal to 50% for patients > 16 years of age and Lansky greater than or equal to 50 for patients less than 16 years of age. Note: Neurologic deficits in patients with CNS tumors must have been relatively stable for a minimum of 1 week 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.