Vinblastine and Carboplatin in Treating Young Patients With Newly Diagnosed or Recurrent Low-Grade Glioma

DISEASE CHARACTERISTICS:

* Histologically confirmed\* low-grade glioma, including 1 of the following subtypes:

  * Astrocytoma variants

    * Fibrillary, protoplasmic, or mixed
  * Pilocytic astrocytoma, including pilomyxoid variants
  * Pleomorphic xanthoastrocytoma
  * Infantile desmoplastic astrocytoma
  * Ganglioglioma
  * Oligodendroglial tumors
  * Mixed glioma, including oligoastrocytoma NOTE: \*Biopsy not required for patients who have visual pathway tumors involving the optic nerves and/or optic radiations (i.e., not isolated to the hypothalamus/chiasm)
* Biopsy proven focal low-grade gliomas of the brainstem with measurable disease allowed

  * No diffuse, intrinsic brainstem tumors
* Residual tumor visible on MRI
* Patients without NF-1 must meet the following criteria:

  * Progressive disease after surgery/biopsy based on clear radiographic or clinical evidence of progression OR gross residual tumor (\> 1.5 cm²) after surgery/biopsy that is felt to be a high risk to the patient for neurologic and/or visual impairment if the tumor progresses
  * Visual pathway tumors that are not isolated to the hypothalamus/chiasm and are not biopsied must be a high risk to the patient for neurologic and/or visual impairment
* Patients with NF-1 must have evidence of radiographic progression on MRI and/or clinical worsening (e.g., worsening of ophthalmologic exam for visual pathway tumors)
* Meets 1 of the following criteria:

  * Newly diagnosed disease
  * Recurrent disease
* No ventriculoperitoneal shunt-related ascites

PATIENT CHARACTERISTICS:

* Karnofsky performance status (PS) 50-100% (for patients \> 10 years of age) OR Lansky PS 50-100% (for patients ≤ 10 years of age)
* Absolute neutrophil count ≥ 1,000/mm³
* Platelet count ≥ 100,000/mm³ (transfusion independent)
* Hemoglobin ≥ 8.0 g/dL (RBC transfusions allowed)
* Creatinine clearance or radioisotope glomerular filtration rate ≥ 70 mL/min OR creatinine based on age, as follows:

  * No greater than 0.8 mg/dL (for patients ≤ 5 years of age)
  * No greater than 1.0 mg/dL (for patients 6-10 years of age)
  * No greater than 1.2 mg/dL (for patients 11-15 years of age)
  * No greater than 1.5 mg/dL (for patients \> 15 years of age)
* Bilirubin ≤ 1.5 times upper limit of normal
* ALT ≤ 110 U/L
* Albumin ≥ 2 g/dL
* No history of allergy to carboplatin
* No hyponatremia requiring treatment
* No uncontrolled infection
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

* See Disease Characteristics
* No prior therapy except for corticosteroids and surgery (for patients with newly diagnosed disease)
* Prior chemotherapy and/or radiotherapy in addition to surgery and corticosteroids allowed (for patients with recurrent disease)
* Prior carboplatin and/or vinblastine allowed if there was no evidence of progressive disease while on therapy and there were no dose reductions due to toxicity (for patients with recurrent disease)
* At least 3 weeks since prior myelosuppressive chemotherapy (6 weeks for nitrosoureas) and recovered (for patients with recurrent disease)
* At least 7 days since prior hematopoietic growth factors (for patients with recurrent disease)
* At least 7 days since prior biological agents (for patients with recurrent disease)
* At least 9 months since prior external beam radiotherapy or gamma knife therapy that included all target lesions (i.e., there is no restriction if a new lesion arises outside the radiation field or a nonirradiated lesion progresses) and recovered (for patients with recurrent disease)
* No other concurrent investigational drugs
* No other concurrent anticancer agents
* No other concurrent chemotherapy, radiotherapy, immunotherapy, or biological therapy
* No concurrent corticosteroids for antiemesis
* Concurrent steroids allowed for tumor edema/increased intracranial pressure provided dose of dexamethasone is stable or decreasing for the past 7 days
* Concurrent physiologic or stress doses of steroids allowed for endocrine deficiencies