Patients receive preparative regimen comprising carmustine IV on days -8 and -3, cytarabine IV every 12 hours and etoposide IV every 12 hours on days -7 to -4, and cyclophosphamide IV on days -2 and -1. PBSC are reinfused on day 0. Patients receive filgrastim (G-CSF) or sargramostim (GM-CSF) beginning after PBSC transplantation. Male patients undergo radiotherapy to the testes before transplantation. Patients with a history of CNS leukemia undergo craniospinal irradiation before transplantation.