Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed prostate cancer, meeting 1 of the following criteria:

- Androgen-dependent disease (testosterone ≥ 250 ng/mL)

- Androgen-independent disease (testosterone < 50 ng/mL)

- Received prior definitive therapy for primary prostate cancer comprising any of the
following:

- External-beam radiotherapy with or without hormonal therapy

- Brachytherapy with or without pelvic external-beam radiotherapy or hormonal
therapy

- Radical prostatectomy with or without adjuvant or salvage radiotherapy

- Cryotherapy

- Must have evidence of disease progression, as evidenced by elevated prostate-specific
antigen (PSA) that has risen serially from post-definitive therapy nadir on 2
determinations taken ≥ 1 week apart

- Elevated PSA, meeting 1 of the following criteria:

- At least 1.0 ng/mL post radiotherapy or cryotherapy

- At least 4 ng/mL post radical prostatectomy

- Must show disease progression after discontinuation of the antiandrogen (for
patients with androgen-dependent disease receiving antiandrogen as part of
primary androgen ablation)

- No metastatic disease, confirmed by negative bone scan and negative CT scan or MRI of
abdomen/pelvis

PATIENT CHARACTERISTICS:

- Karnofsky performance status 70-100%

- Absolute neutrophil count ≥ 1,500/mm³

- Hemoglobin ≥ 8.0 g/dL

- Platelet count ≥ 100,000/mm³

- Creatinine ≤ 1.5 times upper limit of normal (ULN)

- Bilirubin ≤ 1.5 times ULN

- AST ≤ 1.5 times ULN

- No other medical condition that would interfere with study therapy or compliance

- No other active malignancy except previously treated squamous cell or basal cell skin
cancer or cancer that has been treated and considered to be at < 30% risk of relapse

- Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

- See Disease Characteristics

- More than 8 weeks since prior strontium-chloride Sr 89

- More than 4 weeks since first dose of bisphosphonates

- More than 4 weeks since prior major surgery or radiotherapy

- At least 4 weeks since prior hormonal agents, including megestrol or steroids

- Concurrent luteinizing hormone-releasing hormone analogs allowed to maintain
castrate levels of testosterone

- At least 4 weeks since prior and no concurrent saw palmetto, finasteride, or any
herbal agent intended to lower PSA

- Prior adjuvant or neoadjuvant androgen-deprivation therapy allowed for
androgen-dependent prostate cancer provided that all of the following are met:

- No more than 8 months of androgen deprivation

- At least 12 months since last day of effective androgen deprivation

- Testosterone > 250 ng/mL at enrollment

- Prior hormonal therapy, chemotherapy, or investigational therapy for biochemical
relapse allowed

- No concurrent chemotherapeutic, immunotherapeutic, or other investigational agents

- No concurrent radiotherapy

- No concurrent filgrastim (G-CSF) or sargramostim (GM-CSF)