DISEASE CHARACTERISTICS: Histologically proven metastatic (D1 or D2) hormone refractory adenocarcinoma of the prostate with one of the following: -Bidimensionally measurable disease -Bone only metastases with rising PSA levels -PSA only disease defined as rising PSA levels with prior confirmation of D1 or D2 disease PSA must be greater than 8 if bone only or PSA only disease Hormone failure defined as progression after treatment with orchiectomy, LHRH agonist, DES alone, or any hormonal treatment in combination with antiandrogen therapy