Decitabine as Maintenance Therapy After Standard Therapy in Treating Patients With Previously Untreated Acute Myeloid Leukemia

Inclusion Criteria: * Unequivocal histologic diagnosis of AML (\> 20% blasts in the bone marrow based on the World Health Organization \[WHO\] and/or French American British \[FAB\] classifications), excluding M3 (acute promyelocytic leukemia); patients with antecedent myelodysplasia are eligible for treatment on this trial only if there were no bone marrow biopsy showing myelodysplastic syndrome (MDS) \> 3 months prior to enrollment; patients with therapy-related AML are eligible if they have been free of their primary disease and have not received any chemotherapy for at least 2 years * No prior 5-azacitidine or decitabine therapy * No prior treatment for leukemia or myelodysplastic syndrome with four permissible exceptions: * Emergency leukapheresis * Emergency treatment for hyperleukocytosis with hydroxyurea * Cranial radiation therapy (RT) for central nervous system (CNS) leukostasis (one dose only) * Growth factor/cytokine support