Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically proven incurable, metastatic, hormone-refractory adenocarcinoma of the
prostate that is unlikely to respond to existing therapy

- Evidence of tumor by MRI, CT scan, chest x-ray, or radionuclide scan

- Stage D2

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Karnofsky 60-100%

Life expectancy:

- At least 2 months

Hematopoietic:

- Hemoglobin at least 9 g/dL

- 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:

- Creatinine no greater than 2.5 mg/dL

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

Cardiovascular:

- No known chronic heart failure

- 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 severe chronic obstructive pulmonary disease

Other:

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

- Not a high medical or psychiatric risk

- No concurrent nonmalignant systemic disease

- No active infection

PRIOR CONCURRENT THERAPY:

Biologic therapy:

- At least 4 weeks since prior immunotherapy and recovered

Chemotherapy:

- At least 4 weeks since prior chemotherapy and recovered

Endocrine therapy:

- At least 4 weeks since prior hormonal therapy (unless progression documented upon
discontinuation of hormones)

- Concurrent corticosteroids allowed, if stable or decreasing for at least 2 months
before study entry

Radiotherapy:

- At least 4 weeks since prior radiotherapy and recovered

Surgery:

- Recovered from prior surgery

Other:

- Prior cytodifferentiating agent allowed