Calcitriol and Dexamethasone in Treating Patients With Prostate Cancer That Did Not Respond to Hormone Therapy

DISEASE CHARACTERISTICS:

• History of androgen-independent prostate cancer

  • Evidence of rising PSA level (with or without new lesion by radiograph or physical examination), defined as follows:

    • PSA level > 5 ng/mL and clearly rising on 2 measurements taken ≥ 2 weeks apart after androgen deprivation therapy (i.e., orchiectomy or luteinizing hormone-releasing hormone [LHRH] analogue) and antiandrogen withdrawal, if appropriate
  • PSA rising before and on the first value taken at 4 or 6 weeks after antiandrogen cessation is considered disease progression

• Measurable or evaluable disease as defined by any of the following:

  • Measurable or evaluable tumor masses by radiograph or physical examination
  • Evaluable PSA

• Concurrent LHRH analogue or diethylstilbestrol (DES) for testicular androgen suppression required if no prior bilateral orchiectomy

  • Patients receiving other monotherapy for testicular androgen suppression must switch to a LHRH analogue or DES ≥ 14 days prior to study entry

PATIENT CHARACTERISTICS:

• ECOG 0-2
• Life expectancy ≥ 12 weeks
• ANC ≥ 1,000/mm³
• Platelet count ≥ 75,000/mm³
• Hemoglobin > 8.9 g/dL (transfusion or erythropoietin support allowed)
• Serum creatinine ≤ 1.8 mg/dL
• AST ≤ 4 times upper limit of normal (ULN)
• Total bilirubin ≤ 2.0 mg/dL
• Serum corrected calcium < ULN
• No history of nephrolithiasis within the past 5 years
• No unstable, uncontrolled peptic ulcer disease, congestive heart failure, glaucoma, HIV, or diabetes

PRIOR CONCURRENT THERAPY:

• At least 28 days since prior androgen deprivation therapy (≥ 42 days for bicalutamide)

  • A 28-day washout period is not required for patients who have previously progressed despite antiandrogen withdrawal and who have resumed antiandrogens without reduction of PSA
• At least 14 days since prior radiotherapy
• At least 28 days since prior strontium 89
• At least 28 days since prior chemotherapy and/or investigational agents
• No concurrent medications or supplements that contain additional calcium (e.g., Tums)
• No concurrent radiotherapy for pain control or any other indication
• Concurrent bisphosphonates allowed provided dose/regimen is stable