The study was not activated.

RATIONALE: Drugs used in chemotherapy use different ways to stop tumor cells from dividing so they stop growing or die. Giving chemotherapy after surgery may kill more tumor cells.

PURPOSE: Phase II trial to study the effectiveness of mitoxantrone given after surgery in treating patients who have prostate cancer that is at high risk for recurrence.

OBJECTIVES: I. Assess the feasibility of enrolling patients with adenocarcinoma of the prostate at high risk for recurrence following radical prostatectomy in an adjuvant mitoxantrone trial. II. Determine if this adjuvant therapy results in a delay in time to failure or a decrease in the number of treatment failures compared to historical controls in this patient population.

DISEASE CHARACTERISTICS: Adenocarcinoma of the prostate treated by radical prostatectomy within the past 3 months Considered to be at high risk for recurrence as defined by at least 1 of the following characteristics on the radical prostatectomy specimen: Positive seminal vesicles Gleason 6 and preoperative PSA greater than 18 ng/mL Gleason 7 and preoperative PSA greater than 14 ng/mL Gleason 8, 9, or 10 and any preoperative PSA Undetectable PSA (i.e., less than 0.1 ng/mL) within 3 months following radical prostatectomy and at time of enrollment Negative lymph nodes at time of radical prostatectomy if lymphadenectomy performed Extracapsular penetration and/or positive surgical margins allowed

PATIENT CHARACTERISTICS: Age: 18 and over Performance status: Zubrod 0-1 Life expectancy: Not specified Hematopoietic: Granulocyte count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) SGOT no greater than 2 times ULN Renal: Not specified Cardiovascular: No New York Heart Association class III or IV cardiac disease or angina pectoris No myocardial infarction within the past 6 months

PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent filgrastim or sargramostim except for febrile neutropenia Chemotherapy: No other concurrent chemotherapy Endocrine therapy: No prior neoadjuvant or adjuvant hormonal therapy for prostate cancer No concurrent hormonal therapy except for non-disease related conditions (e.g., insulin for diabetes) No concurrent systemic corticosteriods unless for adrenal insufficiency No concurrent prednisone, dexamethasone, or other steroidal antiemetics At least 6 months since prior finasteride No concurrent finasteride No concurrent antiandrogens (e.g., flutamide, bicalutamide, nilutamide) or gonadotropin releasing hormone agonists (e.g., leuprolide, goserelin) Radiotherapy: No prior adjuvant radiotherapy for prostate cancer No prior pelvic radiotherapy for prostate cancer Surgery: See Disease Characteristics Other: At least 6 months since prior saw palmetto No concurrent compounds with 5 alpha-reductase inhibitor activity (e.g., saw palmetto)