3. Concomitant Therapy Patients receiving other therapy (either intrathecal or systemic) designed to treat their leptomeningeal disease are not eligible for this study. Note: Patients receiving concomitant chemotherapy to control systemic disease or bulk CNS disease will be eligible, provided that the systemic chemotherapy is not an investigational agent or one of the following: high-dose methotrexate (> 1g/m2), high-dose cytarabine (> 1g/m2), 5-fluorouracil, capecitabine, thiotepa, a nitrosourea, or topotecan. Please discuss plans for systemic therapy with the Study Chair prior to study entry.