Gemcitabine and Docetaxel in Treating Patients With Metastatic Prostate Cancer

DISEASE CHARACTERISTICS: Histologically confirmed adenocarcinoma of the prostate Androgen-independent metastatic prostate cancer with evidence of clinical, radiographic, or biochemical progression in the setting of castrate levels of testosterone (< 50 mg/dL) No androgen-independent prostate cancer with a rising prostate-specific antigen (PSA) without clinical or radiographic evidence of metastases Clinical or radiographic evidence of metastatic disease with a rising PSA measured 2 times at ≥ 1 week interval allowed Antiandrogen therapy must have been stopped at least 4 weeks (for flutamide) or 6 weeks (for bicalutamide or nilutamide) prior to study entry with evidence of either a rising PSA (from baseline) measured twice at least 2 weeks apart or radiographic evidence of disease progression Testicular androgen suppression (< 50 mg/dL) must be maintained with either luteinizing-hormone releasing-hormone (LHRH) therapy or bilateral orchiectomy No clinical evidence of CNS metastases PATIENT CHARACTERISTICS: ECOG performance status 0-2 Absolute neutrophil count ≥ 1,500/mm^3 Platelet count ≥ 100,000/mm^3 Bilirubin ≤ 1.5 mg/dL AST and ALT ≤ 2 times normal Creatinine < 2 mg/dL No history of severe uncontrolled congestive heart failure (CHF), ventricular dysrhythmias, or severe cardiovascular disease (American Heart Association class III or IV) Disease-free of prior malignancies for ≥ 5 years, with the exception of curatively treated basal cell or squamous cell carcinoma of the skin or low-grade, low-stage bladder cancer No active infection or parenteral antibiotics within 7 days of study entry Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: See Disease Characteristics No radiation therapy within 4 weeks prior to study entry No filgrastim (G-CSF) within 24 hours before or after study therapy No prior systemic chemotherapy for metastatic disease Neoadjuvant or adjuvant non-taxane chemotherapy more than 1 year prior to study entry allowed No concurrent local radiotherapy for control of pain or life-threatening situations