PATIENT CHARACTERISTICS: Age: 18 and over Sex: Male or female Menopausal status: Not specified Performance status: Small cell lung cancer patients: Karnofsky 80-100% Breast cancer patients: Karnofsky 50-100% Life expectancy: Greater than 12 weeks Hematopoietic: Hemoglobin at least 8 g/dL Absolute neutrophil count at least 1,500/mm3 Platelet count at least 100,000/mm3 Hepatic: Bilirubin no greater than 1.5 times upper limit of normal (ULN) AST and ALT no greater than 5 times ULN Renal: Creatinine no greater than 1.7 mg/dL OR Creatinine clearance at least 40 mL/min Cardiovascular: No history of congestive heart failure unless ejection fraction at least 40% Other: No other significant, uncontrolled medical, psychiatric, or surgical condition that would preclude study Not pregnant No nursing during and for 1 month following study Negative pregnancy test Fertile patients must use effective contraception during and for 6 months following study