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