Fludarabine and Busulfan vs. Fludarabine, Busulfan and Total Body Irradiation

Inclusion Criteria: * Diagnosis of acute myelogenous leukemia, chronic myelogenous leukemia, other myeloproliferative disorder, or myelodysplastic syndrome * Any stage of disease will be considered for transplantation * Have a suitable related or unrelated donor (Section 3.3) * Age ≥18 but \<70 yrs * KPS of ≥70% * Recovery from all hematologic and non-hematology toxicities from previous therapies. Exclusion Criteria: * Diagnosis other than acute myelogenous leukemia, myeloproliferative disorder, or myelodysplastic syndrome * Chemotherapy or radiotherapy within 14 days of initiating treatment in this study with the exception of lenalidomide, decitabine, azacitidine, imatinib mesylate, dasatinib, nilotinib hydrochloride and hydroxyurea * Prior dose-intense therapy requiring HSC support within 56 days of initiating treatment in this study * Uncontrolled bacterial, viral, fungal or parasitic infections * Uncontrolled CNS metastases * Known amyloid deposition in heart * Organ dysfunction * LVEF \<40% or cardiac failure not responsive to therapy * FVC, FEV1, or DLCO \<50% of predicted and/or receiving supplementary continuous oxygen * Evidence of hepatic synthetic dysfunction, or total bilirubin \>2x or AST \>3x ULN * Measured creatinine clearance \<20 ml/min * Karnofsky score \<70% * Life expectancy limited by another co-morbid illness * Diagnosed or treated for another malignancy within 3 years of enrollment, with the exception of complete resection of basal cell ca…