Topotecan in Treating Young Patients With Neoplastic Meningitis Due to Leukemia, Lymphoma, or Solid Tumors

DISEASE CHARACTERISTICS: Diagnosis of neoplastic meningitis secondary to leukemia, lymphoma (including AIDS-related lymphoma), or solid tumor (including primary CNS tumors or carcinomas of unknown primary site), defined by 1 of the following criteria: Cerebral spinal fluid (CSF) cell count > 5/μL AND evidence of blast cells on cytospin or by cytology (for patients with leukemia or lymphoma) Presence of tumor cells on cytospin or cytology OR unequivocal presence of meningeal disease by MRI (for patients with solid tumor) No conventional therapy for neoplastic meningitis exists Patients with CNS leukemia or lymphoma must be refractory to conventional therapy, including radiotherapy (i.e., second or greater relapse) Patients with CNS leukemia or lymphoma must have had a negative bone marrow aspiration within the past 2 weeks No clinical evidence of obstructive hydrocephalus No compartmentalization of CSF flow by radioisotope indium In 111 or technetium Tc 99 DTPA flow study No ventriculoperitoneal or ventriculoatrial shunt unless patient is completely shunt-independent No impending spinal cord compression or other CNS involvement (e.g., acute visual loss secondary to optic nerve involvement) requiring emergent local radiotherapy PATIENT CHARACTERISTICS: Age 3 to 21 Performance status Lansky 60-100% (≤ 16 years of age) OR Karnofsky 60-100% (> 16 years of age) Life expectancy Not specified Hematopoietic Not specified Hepatic Not specified Renal Calcium ≥ 7 mg/dL Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception Sodium 125-150 mmol/L Magnesium ≥ 0.7 mmol/L Must have or be willing to have an intraventricular access device (i.e., Ommaya reservoir) No uncontrolled infection HIV-positive patients with AIDS-related lymphomatous meningitis are eligible No other significant uncontrolled systemic medical illness that would preclude study participation PRIOR CONCURRENT THERAPY: Biologic therapy Recovered from prior biologic therapy or immunotherapy Chemotherapy Recovered from prior chemotherapy At least 1 week since prior intra-colony stimulating factory (CSF) chemotherapy (2 weeks for liposomal cytarabine) At least 3 weeks since prior systemic chemotherapy for leptomeningeal disease Concurrent systemic chemotherapy to control systemic disease or bulk CNS disease allowed provided the systemic chemotherapy is not an investigational agent OR any of the following: High-dose (> 1 g/m^2) methotrexate High-dose (> 1 g/m^2) cytarabine Fluorouracil Capecitabine Thiotepa Nitrosoureas Topotecan Endocrine therapy Not specified Radiotherapy See Disease Characteristics At least 8 weeks since prior craniospinal radiotherapy and recovered No concurrent CNS radiotherapy Concurrent radiotherapy to extra-CNS sites (e.g., painful bone metastases not in the craniospinal axis) allowed Surgery Not specified Other More than 2 weeks since prior and no other concurrent investigational agents No other concurrent intra-CSF or systemic therapy for leptomeningeal disease