Liposomal SN-38 in Treating Patients With Small Cell Lung Cancer

DISEASE CHARACTERISTICS: Histologically or cytologically confirmed small cell lung cancer meeting 1 of the following criteria: Previously untreated disease Extensive stage disease, as defined by any of the following: Metastatic disease outside of the chest Contralateral supraclavicular or contralateral hilar nodes that cannot be included in a single radiation port Malignant pleural effusion Previously treated disease Limited or extensive stage disease Measurable disease Lesions ≥ 1 cm and < 2 cm must be measured by spiral CT scan for pre- and post-treatment tumor assessment UGT1A1*28 genotype wt/wt (6/6 promoter TA repeats) OR wt/*28 (6/7 promoter TA repeats) No *28/*28 (7/7 promoter TA repeats) genotype No mixed histology No uncontrolled CNS metastasis Previously treated, stable CNS metastasis allowed No superior vena cava syndrome No malignant pericardial effusion No near obstruction of the trachea or main stem bronchi PATIENT CHARACTERISTICS: Age 18 and over Performance status ECOG 0-2 Life expectancy Not specified Hematopoietic Absolute neutrophil count ≥ 1,500/mm^3 Platelet count ≥ 100,000/mm^3 Hepatic Total bilirubin < 1.5 times upper limit of normal (ULN) OR Direct bilirubin normal Renal Creatinine < 1.5 times ULN Cardiovascular No unstable angina pectoris No uncontrolled congestive heart failure No myocardial infarction within the past 3 months Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception during and for 6 months after study participation No syndrome of inappropriate antidiuretic hormone secretion No ectopic adrenocorticotrophic syndrome No Lambert-Eaton myasthenic syndrome No other severe paraneoplastic syndrome No active infection requiring oral or parenteral antibiotics No other life threatening disease No other malignancy except basal cell or squamous cell skin cancer, localized prostate cancer, superficial bladder cancer, or carcinoma in situ of the cervix PRIOR CONCURRENT THERAPY: Biologic therapy No concurrent filgrastim (G-CSF) during course 1 of study treatment Chemotherapy No more than 1 prior chemotherapy regimen for this malignancy Prior cyclophosphamide, doxorubicin, and vincristine (CAV) alternating with etoposide and cisplatin (EP) allowed More than 21 days since prior chemotherapy Endocrine therapy Not specified Radiotherapy More than 14 days since prior radiotherapy Concurrent palliative radiotherapy allowed except radiotherapy to a solitary measured index lesion Surgery More than 21 days since prior major surgery Other No other concurrent treatment for this malignancy No other concurrent investigational treatment