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