DISEASE CHARACTERISTICS: Histologically confirmed prostate cancer No radiographic evidence of metastatic disease Must show signs of disease progression 3 or more rising PSA values documented, taken at no less than weekly intervals, to greater than 50% above baseline PSA PSA at least 1.0 ng/mL (post prostatectomy) OR 2.0 ng/mL (post radiation) Evaluable disease by serial changes in PSA Progression after primary therapy to include surgery or radiotherapy (with or without neoadjuvant androgen ablation), or intermittent hormonal therapy with noncastrate levels of testosterone (greater than 50 ng/mL) allowed No soft tissue and/or bone disease or androgen independent disease with no evidence of radiographic disease No symptomatic disease or anticipated to be symptomatic within 6 months No active CNS or epidural tumor