PATIENT CHARACTERISTICS: Age: 18 to 75 Performance status: WHO 0-2 Life expectancy: Greater than 3 months Hematopoietic: Absolute neutrophil count greater than 1,500/mm3 Platelet count greater than 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times normal Alkaline phosphatase no greater than 3 times normal SGOT/SGPT no greater than 3 times normal Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No uncontrolled congestive heart failure or angina pectoris in the past 6 months No hypertension or arrhythmia in the past 6 months Neurologic: No peripheral neuropathy No significant neurologic or psychiatric disorder Other: No complete or partial obstruction of the bowel No serious nonmalignant disease No active infection No second malignancy except in situ cervical carcinoma or nonmelanomatous skin carcinoma No chronic diarrhea Not pregnant or nursing Fertile women must use adequate contraception