The purpose of this prostate cancer research study is to investigate:
1. For early-stage patients, the use of a single session of high dose stereotactic body radiotherapy (SBRT) delivered to the tumor within the prostate, not to the entire prostate, as curative treatment of prostate cancer;
2. The addition of ultra short-term androgen supression (uSTAS) to a single session of high dose SBRT as a means of intensifying treatment while preserving quality of life and minimizing side effects;
3. The ability of a single session of high dose SBRT to activate your immune system to enhance eradication