Prospective Evaluation of Stereotactic Body Radiotherapy for Metastatic Prostate Cancer

The investigators aim to test the safety and feasibility of prostate gland stereotactic body radiotherapy (SBRT) plus best systemic therapy in newly diagnosed metastatic prostate cancer.

The investigators and other investigators have previously documented the safety and efficacy of definitive intent stereotactic body radiotherapy (SBRT) in the treatment of localized prostate cancer. In the metastatic setting for multiple malignancies, improved survival rates and disease outcomes have been shown with definitive treatment of the primary disease site. This concept of "cytoreductive" surgery or decreasing the primary tumor burden is now considered the standard of care for metastatic colon, ovarian, renal cell, and some breast carcinomas (plus post-surgery irradiation). With new guidelines and declining rates of PSA screening, the incidence of newly diagnosed metastatic prostate cancer is expected to increase. A recent population-based study has concluded significant improvements in the definitive treatment of the local prostate cancer in the stage IV setting with either radical prostatectomy or conventional prostate radiation treatments/brachytherapy. To our knowledge, one prospective phase II trial is currently accruing patients to best systemic therapy or best systemic therapy (BST) plus definitive treatment with either radical prostatectomy or conventionally fractionated radiation therapy The investigators hypothesize that the addition of primary disease SBRT to best systemic therapy for newly diagnosed metastatic prostate cancer would be associated with an acceptable safety profile, quality of life, disease progression, and overall survival. The addition of SBRT to best systemic therapy is also expected to be better-received for stage IV patients (with relatively limited prognosis), vs. fully fractionated radiation therapy, brachytherapy, or radical prostatectomy. The above endpoints would initially be tested in a prospective phase II multi-institutional trial and in comparison with historical controls.