PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-1 Life expectancy: Greater than 5 years Hematopoietic: Not specified Hepatic: SGOT and alkaline phosphatase no greater than 2 times upper limit of normal No hepatitis B or C or liver cirrhosis Renal: Not specified Other: Fertile patients must use effective contraception No other prior malignancy in past 5 years except carcinoma in situ or nonmelanoma skin cancer