PATIENT CHARACTERISTICS: Age: 18 to 64 Performance status: ECOG 0-2 Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Bilirubin no greater than 1.5 mg/dL Transaminase no greater than 3.0 times upper limit of normal Renal: Creatinine no greater than 1.7 mg/dL Other: Not pregnant or nursing Fertile patients must use effective contraception No other prior or concurrent malignancies except curatively treated (by radiotherapy or surgery) basal cell skin cancer or carcinoma in situ