Radiation Therapy With or Without Antiandrogen Therapy in Treating Patients With Stage I or Stage II Prostate Cancer

OBJECTIVES: Primary: To evaluate whether a combination of Zoladex and flutamide used as cytoreductive agents prior to and during definitive radiation therapy improves overall survival over radiation therapy alone in locally confined carcinomas of the prostate; Secondary: To compare the rates of disease-specific survival, clinical relapse (local progression and/or distant failure), freedom from prostate-specific antigen (PSA) failure, freedom from second clinical relapse, freedom from second PSA relapse, and disease-free survival; To compare the prostate re-biopsy at two years; To measure the effect on sexual function. OUTLINE: This is a randomized, multicenter study. Patients were stratified by PSA level (less than 4 vs 4-20), tumor differentiation (well vs moderate vs poor), nodal status (N0 \[nodes evaluated by surgical sampling\] vs NX \[nodes evaluated negative by imaging methods only\]), and participating center. Patients are randomized to one of two treatment arms. Arm I: Patients receive oral flutamide 3 times a day and goserelin subcutaneously once every 4 weeks, or once as a time release injection (intramuscular leuprolide may be substituted for goserelin), beginning 2 months prior to radiotherapy and continuing until completion of radiotherapy. Patients undergo radiotherapy daily 4-5 days per week for almost 8 weeks. Arm II: Patients undergo radiotherapy only, as in arm I. Patients are followed every 3 months for the remainder of the first year, every 4 months for the second year, every 6 months for the third through fifth years, and then annually thereafter. PROJECTED ACCRUAL: A total of 1980 patients within 5 years.