Flu/TBI in Treating Patients Not Responding to Previous Hormone Therapy

OBJECTIVES: * Determine the treatment-related mortality in patients with hormone-refractory, progressive metastatic prostate cancer treated with nonmyeloablative conditioning comprising fludarabine and total-body irradiation followed by allogeneic hematopoietic stem cell transplantation. OUTLINE: * Nonmyeloablative conditioning regimen: Patients receive fludarabine IV on days -4 to -2 and total-body irradiation (TBI) on day 0. * Allogeneic hematopoietic stem cell transplantation (AHSCT): After TBI, patients undergo AHSCT on day 0. * Immunosuppression: Patients receive oral cyclosporine twice daily on days -3 to 56 followed by a taper until day 81. Patients also receive oral mycophenolate mofetil twice daily on days 0-27 (if patient has a related donor) OR three times daily on days 0-29 and then twice daily on days 30-149 followed by additional tapering until day 180 (if patient has an unrelated donor). PROJECTED ACCRUAL: A total of 10 patients will be accrued for this study.