- Solid Tumors: History of untreated metastatic CNS tumor involvement. Extradural masses which have not invaded the brain parenchyma or parameningeal tumors without evidence for leptomeningeal spread will not render the patient ineligible. Patients with previous CNS tumor involvement are eligible IF the CNS tumor(s) has been treated and has been stable or resolving for at least 4 weeks; and if the patient does not currently require steroids.