PATIENT CHARACTERISTICS: Age: 15 to 60 Performance status: Not specified Hematopoietic: Not applicable Hepatic: Bilirubin no greater than 1.5 x ULN Renal: Creatinine no greater than 1.5 x ULN Cardiovascular: No severe heart failure requiring diuretics or with an LVEF less than 50% Other: No severe concomitant neurologic disease No severe concomitant psychologic disease