RATIONALE: Conformal radiation therapy uses a 3-dimensional (3-D) image of the tumor to help focus thin beams of radiation directly on the tumor. Giving conformal external-beam radiation therapy in higher doses over a shorter period of time may kill more tumor cells and have fewer side effects. Androgens can cause the growth of prostate cancer cells. Hormone therapy, such as leuprolide acetate, may lessen the amount of androgens made by the body. It is not yet known whether radiation therapy is more effective when given together with or without hormone therapy in treating patients with prostate cancer who have undergone surgery.