DISEASE CHARACTERISTICS: Histologically or cytologically proven leukemia of any of the following types: Acute myelogenous leukemia (AML) Newly diagnosed de novo AML in patients over 60 years with poor risk features Antecedent hematologic disorder Complex karyotypes or other adverse cytogenetics Stem cell immunophenotype AML arising from myelodysplastic syndrome Secondary AML Recurrent or refractory AML, including primary induction failure Acute lymphoblastic leukemia (ALL) Newly diagnosed de novo ALL in patients over 60 years with poor risk disease features Complex karyotype or other adverse cytogenetics Mixed lineage immunophenotype Recurrent or refractory ALL, including primary induction failure Chronic myelogenous leukemia in accelerated phase or blast crisis No more than 2 prior induction/reinduction therapy courses if failed primary induction therapy or relapsed following complete remission Not eligible for or refused allogeneic bone marrow transplantation Acute progranulocytic leukemia (M3) must meet following criteria: Prior treatment with tretinoin required No coagulopathy Low risk for developing coagulopathy No disseminated intravascular coagulation No CNS leukemia