PATIENT CHARACTERISTICS: Age: Over 18 Performance Status: ECOG 0-2 Life Expectancy: Greater than 3 months Hematopoietic: Absolute neutrophil count at least 1,500/mm3 Platelet count at least 50,000/mm3 Hepatic: Not specified Renal: Creatinine no greater than 1.5 mg/dL Creatinine clearance at least 40 mL/min Cardiovascular: No symptomatic congestive heart failure (class III or more as defined by American Heart Association) Electrolytes: Potassium at least 3.4 meq/L Magnesium at least 1.4 meq/L Other: Not pregnant or nursing