PEG-Interferon Alfa-2b in Treating Young Patients With Plexiform Neurofibroma

DISEASE CHARACTERISTICS:

* Diagnosis of plexiform neurofibroma which is progressive, symptomatic, or life threatening and for which there is no other standard medical management or surgical option
* Histologic confirmation of tumor is not required in the presence of consistent clinical and radiographic findings provided the following are true:

  * No clinical observation or scan suggestive of malignant transformation
  * Meets ≥ 1 of the following diagnostic criteria for neurofibroma type 1 (NF1):

    * Six or more cafe-au-lait spots (\> 0.5 cm in prepubertal patients or \> 1.5 cm in post pubertal patients)
    * Freckling in axilla or groin
    * Optic glioma
    * Two or more Lisch nodules
    * A distinctive bony lesion (e.g., dysplasia of the sphenoid bone, dysplasia, or thinning of long bone cortex)
    * A first degree relative with NF1
* No history of malignant peripheral nerve sheath tumor
* No active visual pathway glioma
* No active brain tumor or brain metastases

PATIENT CHARACTERISTICS:

Performance status

* ECOG 0-2

Life expectancy

* At least 12 months

Hematopoietic

* Absolute neutrophil count \> 1,500/mm\^3
* Hemoglobin \> 10 g/dL
* Platelet count \> 100,000/mm\^3

Hepatic

* Bilirubin \< 1.5 mg/dL
* SGPT ≤ 2 times upper limit of normal
* No significant hepatic dysfunction

Renal

* Creatinine based on age as follows:

  * ≤ 0.8 mg/dL (for patients age 5 years and under)
  * ≤ 1.0 mg/dL (for patients age 6 to 10 years)
  * ≤ 1.2 mg/dL (for patients age 11 to 15 years)
  * ≤ 1.5 mg/dL (for patients age 16 to 21 years) OR
* Creatinine clearance ≥ 70 mL/min

Cardiovascular

* No significant cardiac dysfunction
* No severe cardiovascular disease
* No cardiac arrhythmia requiring chronic treatment
* No congestive heart failure
* No symptomatic ischemic heart disease

Pulmonary

* No significant pulmonary dysfunction

Other

* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* No serious infection
* No other significant unrelated systemic illness
* No significant organ dysfunction
* No other malignancy except surgically cured nonmelanoma skin cancer or carcinoma in situ of the cervix
* No history of severe psychiatric condition or psychiatric disorder requiring hospitalization
* No history of suicidal ideation or attempt
* No thyroid dysfunction unresponsive to therapy
* No uncontrolled diabetes mellitus
* No history of HIV positivity
* No alcohol or drug abuse

PRIOR CONCURRENT THERAPY:

Biologic therapy

* No concurrent immunotherapy
* No concurrent colony-stimulating factors (e.g., erythropoietin or filgrastim \[G-CSF\])

Chemotherapy

* No concurrent chemotherapy for this disease

Endocrine therapy

* No concurrent chronic systemic corticosteroids
* No concurrent hormonal therapy for this disease

Radiotherapy

* No concurrent radiotherapy for this disease

Surgery

* Prior surgery allowed provided it has been at least 21 days since surgery and there is presence of residual tumor

Other

* Recovered from prior therapy
* More than 30 days since prior investigational agents