DISEASE CHARACTERISTICS: Histologically proven asymptomatic recurrent prostate cancer Prior local treatment status Curatively treated OR Locally advanced disease noncuratively treated with LHRH agonist therapy Currently receiving 1 line of hormonal therapy (with LHRH agonists or surgical castration) and failing treatment with rising PSA only Patients who received LHRH agonists instead of surgical castration continue to receive LHRH agonist during study Biochemical progression documented by 3 consecutively rising PSA measurements, each at least 2 weeks apart, with the last measurement being 50% or greater than the nadir PSA achieved after the last therapeutic maneuver (first line hormonal therapy as noted above) PSA (50% increased values) greater than 4 ng/mL for patients with intact prostates and greater than 0.8 ng/mL for post-prostatectomy patients Rising PSA for less than 10 months Castrate levels of testosterone (less than 30 ng/dL) No bone or visceral metastases by bone scan and CT scan of abdomen and pelvis (except localized abnormalities and pelvic lymph node and soft tissue disease) No CNS or leptomeningeal involvement