A Multi-Center Study of Nonmyeloablative Conditioning With TBI or Fludarabine/TBI for HLA-matched Related Hematopoietic Cell Transplantation for Treatment of Hematologic Malignancies With Post Grafting Immunosuppression With Tacrolimus and Mycophenolate Mofetil

PRIMARY OBJECTIVES: I. To estimate the incidence of grade III/IV graft-versus-host disease (GVHD) after conditioning with 200 centigray (cGy) TBI alone or Fludarabine (fludarabine phosphate)/200 cGy TBI followed by tacrolimus (Tac)/mycophenolate mofetil (MMF) immunosuppression in patients with hematologic malignancies. II. To estimate the incidence of chronic extensive GVHD. SECONDARY OBJECTIVES: I. To estimate the incidences of graft rejection. II. To estimate overall survival 1-year after conditioning. III. To evaluate the incidences of grades II-IV acute GVHD. IV. To evaluate the rates of disease progression and/or relapse-related mortality. V. To estimate the rate and duration of steroid use for the treatment of chronic GVHD. OUTLINE: Patients are assigned to 1 of 2 treatment arms. ARM I (nonmyeloablative conditioning with fludarabine phosphate and TBI): Patients receive fludarabine phosphate intravenously (IV) on days -4 to -2 and undergo TBI on day 0. ARM II (nonmyeloablative conditioning with TBI): Patients undergo TBI on day 0. All patients then undergo allogeneic peripheral blood stem cell transplantation on day 0 and receive tacrolimus orally (PO) every 12 hours on days -3 to 180, with taper on day 56, or tacrolimus IV if unable to tolerate PO; and mycophenolate mofetil PO every 12 hours on days 0-27 or mycophenolate mofetil IV if unable to tolerate PO. Treatment continues in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 6 months for 2 years and then annually for 3 years.