Combination Chemotherapy in Treating Children With Newly Diagnosed Acute Myeloid Leukemia or Myelodysplastic Syndrome

RATIONALE: Drugs used in chemotherapy use different ways to stop cancer cells from dividing so they stop growing or die. Combining more than one drug may kill more cancer cells. It is not yet known which regimen of combination chemotherapy is more effective for acute myeloid leukemia or myelodysplastic syndrome. PURPOSE: Randomized phase III trial to compare the effectiveness of different combination chemotherapy regimens in treating children who have newly diagnosed acute myeloid leukemia or myelodysplastic syndrome.