DISEASE CHARACTERISTICS: Histologically proven prostate cancer that is androgen dependent or independent Androgen dependent disease must meet ONE OR MORE of the following criteria: (1) Previously untreated, locally advanced adenocarcinoma of the prostate and: T1-2 tumor stage, PSA greater than 20 ng/mL OR T3-4 tumor stage OR Gleason grade 8-10 (2) Small cell carcinoma, poorly differentiated tumor with neuroendocrine features, or neuroendocrine carcinoma of any stage (3) Disease metastatic to bones or soft tissues (visceral or lymph nodes) that is evaluable on MRI, CT, or bone scan (patients with evaluable disease that relapsed after neoadjuvant hormone therapy prior to radical prostatectomy or radiotherapy are eligible) Patients meeting one of the above criteria who have started on an antiandrogen (flutamide, nilutamide, or bicalutamide) and/or a gonadotropin releasing hormone (GnRH) analog (luprolide or goserelin) are eligible if they have been on androgen ablation (GnRH analog with or without antiandrogen) for no more than 3 months Androgen independent disease must meet ALL of the following criteria: (1) Disease progression despite primary hormone treatment (e.g., orchiectomy, estrogen therapy, GnRH analog with or without an antiandrogen), OR disease progression despite receiving antiandrogen treatment as part of primary hormone therapy, evidenced by: Bone (new osseous lesion) or Soft tissue (greater than 25% increase in bidimensionally measurable disease) or Rising PSA (on any 3 determinations taken at weekly intervals (at least) to greater than 50% above the patient's baseline PSA value) despite castrate (no greater than 30 ng/mL) levels of testosterone (2) At least 2 weeks since change in hormone therapy (including prednisone or dexamethasone) (3) Continuation on treatments to maintain castrate levels of testosterone if no prior orchiectomy (4) Evaluable or measurable disease (5) No more than 1 prior course of chemotherapy (6) No more than 1 prior course of palliative radiotherapy or radioisotope treatment (strontium chloride Sr 89)