Thalidomide and Cyclophosphamide in Treating Children With Recurrent or Refractory Childhood Cancers

DISEASE CHARACTERISTICS: Histologically or cytologically proven pediatric malignancy, except when there is appearance consistent with brainstem tumor on MRI, a tumor marker positive for germ cell tumor, or ophthalmologic diagnosis of intraocular retinoblastoma Failed conventional treatment or conventional therapy is not available Measurable disease by MRI, CT scan, biochemical tumor markers, cytology, or bone marrow examination PATIENT CHARACTERISTICS: Age: Not specified Performance status: Lansky 60-100% OR Karnofsky 60-100% Life expectancy: At least 6 weeks Hematopoietic: Absolute neutrophil count at least 750/mm3 (between 300-750/mm3, if due to bone marrow infiltration by malignancy) Platelet count at least 75,000/mm3 (between 20,000-75,000/mm3, if due to bone marrow infiltration by malignancy) Hepatic: Bilirubin less than 2.0 mg/dL ALT less than 3 times upper limit of normal (ULN) Renal: Creatinine less than 2 times ULN OR Creatinine clearance at least 70 mL/min Neurologic: No peripheral neuropathy grade 3 or 4 No seizure disorder in patients without CNS malignancies Other: Not pregnant or nursing Negative pregnancy tests during study and for 1 month after final dose of thalidomide Fertile patients must use effective contraception during and for at least 1 month after study PRIOR CONCURRENT THERAPY: See Disease Characteristics No limit on the number of prior agents or regimens received Biologic therapy: Prior bone marrow transplantation allowed Chemotherapy: Recovered from prior chemotherapy No prior thalidomide Endocrine therapy: Not specified Radiotherapy: Not specified Surgery: At least 4 weeks since prior major surgery (2 weeks for minor surgery, excluding central venous catheter placement procedures)