DISEASE CHARACTERISTICS:

• Histologically confirmed prostate cancer

  • Stage D0 disease

    • Disease limited to the prostate

      • Seminal vesicle involvement allowed provided all visible disease was removed by surgery

• Rising prostate-specific antigen (PSA) after completing primary local therapy (surgery and/or radiotherapy) for prostate cancer ≥ 3 months ago

  • PSA ≥ 2 ng/mL documented by 2 measurements taken ≥ 4 weeks apart with a doubling time of ≤ 8 months

    • Final PSA measurement must be obtained within 1 week prior to study entry

• Negative CT scan of the chest, abdomen, and pelvis and bone scan

  • Scans must be completed within 4 weeks prior to study entry

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• At least 6 months

Hematopoietic

• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 10 g/dL

Hepatic

• SGOT and SGPT ≤ 1.5 times upper limit of normal
• Bilirubin ≤ 1.5 mg/dL
• No uncontrolled hepatic disease

Renal

• Creatinine ≤ 1.5 mg/dL
• No uncontrolled renal disease

Cardiovascular

• No uncontrolled cardiac disease

Other

• Fertile patients must use effective barrier contraception during and for 4 weeks after completion of study treatment
• No active infection
• No known HIV positivity
• No other uncontrolled medical condition, defined as ≥ grade 3
• No uncontrolled psychiatric disease
• No diagnosis of major depression or suicidal ideation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• Not specified

Chemotherapy

• More than 5 years since prior chemotherapy
• No prior treatment with cyclophosphamide or etoposide that lasted for > 2 months

Endocrine therapy

• At least 1 year since prior androgen-ablation therapy and recovered

  • No disease progression during therapy

Radiotherapy

• See Disease Characteristics
• Recovered from prior radiotherapy

Surgery

• See Disease Characteristics
• Recovered from prior surgery

Other

• No other concurrent investigational agents
• No concurrent cyclosporine, succinylcholine chloride, or phenobarbital