RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Colony-stimulating factors such as filgrastim may increase the number of immune cells found in bone marrow or peripheral blood and may help a person's immune system recover from the side effects of chemotherapy.

PURPOSE: Phase II trial to study the effectiveness of combination chemotherapy plus filgrastim in treating patients who have stage IV prostate cancer that has not responded to hormone therapy.

OBJECTIVES: I. Determine the response rate (objective and PSA response) and duration of response to estramustine, docetaxel, and carboplatin with filgrastim (G-CSF) support in patients with hormone refractory prostate cancer. II. Determine the toxicity of this regimen in this patient population.

OUTLINE: Patients receive oral estramustine 3 times daily on days 1-5. Patients receive docetaxel IV over 1 hour followed by carboplatin IV over 1 hour on day 2. Filgrastim (G-CSF) SC is administered beginning on day 6 and continuing until hematopoietic recovery. Treatment continues every 21 days in the absence of unacceptable toxicity or disease progression. Patients are followed every 3 months for a maximum of 2 years.

PROJECTED ACCRUAL: A total of 39 patients will be accrued for this study within 10 months.

• Biological: filgrastim
• Drug: carboplatin
• Drug: docetaxel
• Drug: estramustine phosphate sodium

DISEASE CHARACTERISTICS: Histologically confirmed stage IV adenocarcinoma of the prostate Failure on standard hormone therapy Measurable disease with any PSA Accurately measured in at least 1 dimension as at least 20 mm by physical exam for clinically palpable lymph nodes and superficial skin lesions or chest x-ray for clearly defined lung lesions surrounded by aerated lung OR those lesions measured as at least 10 mm by spiral CT scan OR Nonmeasurable disease with PSA at least 5 ng/mL Nontarget lesions including small lesions with longest diameter less than 20 mm by conventional techniques or less than 10 mm by spiral CT scan and truly nonmeasurable lesions including: Bone lesions Pleural or pericardial effusions Ascites CNS lesions Leptomeningeal disease Irradiated lesions unless progression documented after radiotherapy Documented progressive systemic disease despite at least 1 endocrine manipulation with either orchiectomy or LHRH agonist (which must be continued), or diethylstilbestrol For measurable disease: Objective evidence of increase of greater than 20% in the sum of the longest diameters of target lesions from the time of maximal regression or the appearance of 1 or more new lesions For nonmeasurable disease: If bone only disease, appearance of 1 new lesion on bone scan attributable to prostate cancer along with a PSA of at least 5 ng/mL OR An elevated PSA (at least 5 ng/mL) that has risen serially from baseline on 2 occasions each at least 1 week apart Testosterone no greater than 50 ng/mL if no prior bilateral orchiectomy

PATIENT CHARACTERISTICS: Age: 18 to 99 Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: WBC at least 3,000/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.0 times upper limit of normal (ULN) AST no greater than 1.5 times ULN Renal: Creatinine no greater than 1.5 times ULN Cardiovascular: No myocardial infarction or significant change in anginal pattern within past 1 year No congestive heart failure No New York Heart Association class II-IV heart disease No deep venous thrombosis or pulmonary embolus within past 1 year Other: Fertile patients must use effective contraception No clinically significant peripheral neuropathy No known hypersensitivity to E. coli derived products

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent sargramostim (GM-CSF) Chemotherapy: No prior chemotherapy No prior estramustine or suramin No other concurrent chemotherapy Endocrine therapy: See Disease Characteristics At least 4 weeks since prior antiandrogens Primary testicular androgen suppression (e.g., with an LHRH analogue) should not be discontinued Concurrent LHRH analogue allowed if no prior bilateral orchiectomy Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiation and recovered At least 8 weeks since prior strontium chloride Sr 89 or samarium Sm 153 lexidronam pentasodium No concurrent palliative radiotherapy Surgery: See Disease Characteristics At least 4 weeks since prior major surgery and recovered