PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: Not specified Hematopoietic: WBC at least 4,000/mm3 Platelet count at least 125,000/mm3 Hematocrit at least 33% Hepatic: AST no greater than 2 times upper limit of normal (ULN) LDH no greater than 2 times ULN Alkaline phosphatase no greater than 2 times ULN Bilirubin no greater than 2 times ULN If LDH or alkaline phosphatase are above normal, CT or MRI of liver required Renal: Creatinine no greater than 1.8 mg/dL BUN no greater than 33 mg/dL Other: Not pregnant or nursing Fertile patients must use effective contraception No other prior or concurrent malignancies within 2 years, except any carcinoma in situ, lobular carcinoma of the breast in situ, carcinoma in situ of the cervix, atypical melanocytic hyperplasia or Clark I melanoma in situ, or basal or squamous cell skin cancer