Stage IIIB Prostate Cancer American Joint Committee on Cancer (AJCC) v8

This phase II trial investigates the effect of extremely hypofractionated intensity modulated stereotactic body radiotherapy in treating patients with prostate cancer that has rising prostate specific antigen (PSA) after radical prostatectomy. Stereotactic body radiation therapy uses special equipment to position a patient and deliver radiation to tumors with high precision. This method may kill tumor cells with fewer doses over a shorter period and cause less damage to normal tissue. Hypofractionated radiation therapy delivers higher doses of radiation therapy over a shorter period of time and may kill more tumor cells and have fewer side effects.