DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed adenocarcinoma of the prostate

  • No neuroendocrine or small cell features
• No evidence of metastatic disease
• Planning radical prostatectomy at least 2 months from now
• Testosterone level normal

PATIENT CHARACTERISTICS:

• ECOG performance status (PS) 0-1 or Karnofsky PS 70-100%
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• Hemoglobin ≥ 8 g/dL
• AST and ALT ≤ 1.5 times upper limit of normal (ULN)
• Bilirubin ≤ 1.5 times ULN
• Creatinine ≤ 1.5 times ULN
• PT and PTT normal
• Fertile patients must use effective barrier contraception
• No history of allergic reaction to compounds of similar chemical or biologic composition to sargramostim (GM-CSF)
• No ongoing or active bacterial, viral, or fungal infection
• DLCO > 50% if patient has a history of clinically significant obstructive airway disease
• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia
• No other active malignancy, defined as cancer for which therapy has been completed and patient is now considered < 30% risk of relapse, except nonmelanoma skin cancer
• No psychiatric illness or social situation that would preclude study compliance
• No other uncontrolled illness
• No underlying medical condition that, in the opinion of the principal investigator, may make the administration of GM-CSF hazardous or obscure the interpretation of adverse events

PRIOR CONCURRENT THERAPY:

• More than 4 weeks since prior major surgery
• No prior radiotherapy, immunotherapy, chemotherapy, or other investigational therapy for this cancer

• No prior hormonal therapy including any of the following:

  • Luteinizing-hormone releasing hormone (LHRH) agonists
  • LHRH antagonists

  • Antiandrogens, including any of the following:

    • Bilcalutamide
    • Flutamide
    • Nilutamide
  • 5-alpha-reductase inhibitors
  • PC-SPES or other PC-x product
  • Estrogen-containing nutriceuticals
• No concurrent chemotherapy or radiotherapy

• No concurrent systemic steroid therapy

  • Concurrent inhaled or topical steroids allowed
• No other concurrent immunotherapy
• No other concurrent investigational agent
• No other concurrent anticancer agents or therapies