RATIONALE: Androgens can cause the growth of prostate cancer cells. Antihormone therapy, such as leuprolide and bicalutamide, may lessen the amount of androgens made by the body. Implant radiation therapy kills tumor cells by placing material such as radioactive iodine directly into or near a tumor. Giving leuprolide and bicalutamide together with implant radiation therapy may kill more tumor cells.