RATIONALE: Radiation therapy uses high energy x rays to kill tumor cells. This may be an effective treatment for prostate cancer. Androgens can cause the growth of prostate cancer cells. Antihormone therapy, such as goserelin and cyproterone, may lessen the amount of androgens made by the body and reduces the amount of androgens available to the body. It is not yet know whether radiation therapy alone is more effective than radiation therapy given together with goserelin and cyproterone in treating patients with prostate cancer.

PURPOSE: This randomized phase III trial is studying radiation therapy to see how well it works compared to giving radiation therapy together with goserelin and cyproterone in treating patients with prostate cancer that is at high risk for metastasis.

OBJECTIVES: I. Evaluate the ability of adjuvant hormone therapy with an LHRH agonist (Goserelin depot) to produce an increased disease-free survival and to prolong overall survival when initiated during the first week of radiotherapy in prostatic cancer patients with a high risk of developing metastatic disease.

OUTLINE: Randomized study. Arm I: Radiotherapy. Whole-pelvic irradiation using photons with a recommended energy of at least 10 MV (Co60 therapy is acceptable if higher energy unavailable). Arm II: Radiotherapy plus 2-Drug Combination Hormonal Therapy. Whole-pelvic irradiation as in Arm I; plus Goserelin, ZDX, NSC-606864; Cyproterone acetate, CPTR, NSC-81430.

PROJECTED ACCRUAL: 400 patients will be entered over 5 years. At least 75 patients on each arm should be followed until relapse.

DISEASE CHARACTERISTICS: Histologically proven prostatic adenocarcinoma of the following TNM stages and WHO grades: T1 or T2 and grade G3 T3 or T4 and any histologic grade No evidence of distant metastases No evidence of positive common iliac or para-aortic lymph nodes Confirmed by bone scan, chest x-ray, negative ultrasound or CT of the liver, and CT of the retroperitoneum and/or bipedal lymphangiography Extraperitoneal pelvic lymph node biopsy may be either positive or negative provided stage and grade criteria are met

PATIENT CHARACTERISTICS: Age: Under 80 Performance status: WHO 0-2 Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Other: No history of second malignancy except basal cell skin carcinoma

PRIOR CONCURRENT THERAPY: Biologic therapy: Not specified Chemotherapy: No prior chemotherapy for prostate cancer Endocrine therapy: No prior hormonal therapy for prostate cancer Radiotherapy: No prior radiotherapy for prostate cancer Surgery: No prior radical prostatectomy No prior transperitoneal lymph node staging