Radiation Therapy in Treating Patients With Metastatic Hormone-Resistant Prostate Cancer Receiving Sipuleucel-T

PRIMARY OBJECTIVES: I. To assess whether radiation therapy (RT) increases the immunogenic potential or sipuleucel-T in participants with castration recurrent prostate cancer. II. To assess systemic changes to the immune system and genetic changes to immune cells in participants treated by the combination of RT and sipuleucel-T. III. To assess the induction of antigen-specific immune responses to prostatic acid phosphatase (PAP), cancer/testis antigen 1B (NY-ESO-1) and antigens that have proven to be released by radiation (such as, heat shock protein 90 \[HSP-90\], calreticulin, etc.). SECONDARY OBJECTIVES: I. To assess adverse event rates in participants receiving the high-dose radiation and sipuleucel-T therapy. II. To assess prostate-specific antigen (PSA) changes. III. To assess overall and cancer specific survival. OUTLINE: Patients undergo single-fraction radiation therapy to at least 1 bone lesion 2 days after the first sipuleucel-T dose. After completion of study treatment, patients are followed up at 3 and 6 months and then annually thereafter.