Preparative regimen/transplantation: Patients receive carboplatin IV over 1 hour and etoposide IV continuously on days -6 to -4. Cyclophosphamide is administered IV over 1 hour on days -3 and -2 or IV continuously on days -3 and -2, -4 to -2, -5 to -2, or -6 to -2. PBSC or bone marrow is reinfused on day 0.