Topotecan and Paclitaxel in Treating Patients With Recurrent or Refractory Small Cell Lung Cancer

DISEASE CHARACTERISTICS: * Stratum A (less than 3 months since prior therapy) closed to accrual effective 06/20/2000) * Histologically or cytologically confirmed recurrent or refractory small cell lung cancer * Only 1 prior regimen allowed (an alternating regimen with cyclophosphamide/doxorubicin/vincristine and etoposide/cisplatin is acceptable) * No mixed histology * Measurable or evaluable disease that has not been in the field of prior radiotherapy * No uncontrolled CNS metastases (treated CNS metastases eligible) PATIENT CHARACTERISTICS: Age: * 18 and over Performance status: * ECOG 0-2 Hematopoietic: * Absolute neutrophil count at least 2,000/mm\^3 * Platelet count at least 100,000/mm\^3 Hepatic: * Total bilirubin no greater than 1.5 times upper limit of normal (ULN) OR * Direct bilirubin normal Renal: * Creatinine no greater than 1.5 times ULN Cardiovascular: * No unstable angina pectoris * No uncontrolled congestive heart failure * No myocardial infarction within the past 3 months Other: * No uncontrolled infections * No other concurrent malignancy except skin cancer or localized prostate cancer * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: * Not specified Chemotherapy: * See Disease Characteristics * No prior topoisomerase I inhibitor (e.g., topotecan or irinotecan) or taxane (e.g., paclitaxel or docetaxel) * At least 3 months since other prior chemotherapy Radiotherapy: * See Disease Characteristics * At least 2 weeks since prior radiotherapy * No concurrent radiotherapy Surgery: * At least 3 weeks since any prior major surgery