Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed incurable neuroendocrine tumor that is unlikely to respond
to existing therapy, meeting 1 of the following criteria:

- Metastatic disease

- Disease that is not curable with surgery or radiotherapy

- Measurable disease by MRI or CT scan

- Tumor must be at least 2 cm

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- At least 2 months

Hematopoietic:

- WBC at least 2,000/mm^3

- Platelet count at least 50,000/mm^3

Hepatic:

- No hepatic insufficiency

- Bilirubin no greater than 2.5 mg/dL

- SGOT and SGPT no greater than 5 times upper limit of normal

Renal:

- No renal insufficiency

- Creatinine no greater than 2.5 mg/dL

- No history of renal conditions that contraindicate high dosages of sodium

Cardiovascular:

- No uncontrolled hypertension

- No history of congestive heart failure

- No history of other cardiovascular conditions that contraindicate high dosages of
sodium

Pulmonary:

- No serious lung disease, such as chronic obstructive pulmonary disease

Other:

- Not pregnant or nursing

- Fertile patients must use effective contraception during and for 4 weeks after study
participation

- No active infection

- No concurrent nonmalignant systemic disease

- Not a high medical or psychiatric risk

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 4 weeks since prior immunotherapy

- No concurrent immunomodulating agents

Chemotherapy:

- At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas)

Endocrine therapy:

- Concurrent corticosteroids allowed

Radiotherapy:

- At least 8 weeks since prior radiotherapy

Surgery:

- Recovered from prior surgery

Other:

- Prior cytodifferentiating agents allowed

- No prior antineoplastons

- No other concurrent antineoplastic agents