DISEASE CHARACTERISTICS:

Inclusion criteria:

   - Histologically or cytologically confirmed small cell lung cancer (SCLC)

   - If patient is treatment-naive, then they must have extensive disease

   - If patients are not treatment-naive, then they must be classified as sensitive-relapse
   with either extensive disease or limited disease

      - Sensitive-relapse defined as disease that responded to first-line chemotherapy
      and relapsed more than 90 days following the last dose of first-line chemotherapy

      - Limited disease SCLC defined as disease confined to the hemithorax of origin,
      mediastinum, and/or ipsilateral supraclavicular lymph nodes, which could be
      encompassed within a tolerable radiotherapy port

      - Extensive disease defined as disease that does not fit the definition of limited
      disease as defined above

   - Measurable or evaluable disease

Exclusion criteria:

   - Active central nervous system (CNS) metastases, defined as metastases to the CNS
   (symptomatic or non-symptomatic) that requires immediate treatment or that are likely
   to require treatment in the following 6 weeks

   - Medical conditions requiring urgent intervention, including any of the following:

      - Superior vena cava syndrome

      - Lobar obstruction

      - Spinal cord compression

      - Liver metastases involving greater than one-third of the liver

PATIENT CHARACTERISTICS:

Inclusion criteria:

   - Eastern Cooperative Oncology Group (ECOG) performance status of 0-2

   - Absolute neutrophil count ≥ 1,500/mm^3

   - Platelet count ≥ 100,000/mm^3

   - Hemoglobin ≥ 9 g/dL (no red blood cell transfusions allowed)

   - Serum bilirubin ≤ 1.5 x upper limit of normal (ULN)

   - Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) ≤ 5 x ULN (if
   liver metastases are present) or ≤ 2 x ULN (if liver metastases are absent)

   - Serum creatinine ≤ 1.5 x ULN

   - Not pregnant or nursing

   - Negative pregnancy test

   - Fertile patients must use effective contraception during and for at least 30 days
   after completion of study treatment

Exclusion criteria:

   - Prior or concurrent malignancies, except for adequately treated basal cell or squamous
   cell carcinoma of the skin, carcinoma in situ of the cervix, or localized low-grade
   prostate cancer

   - Hyponatremia (< 130 mmol/L)

   - Evidence of a significant medical disorder or laboratory finding that, in the opinion
   of the investigator, compromises the patient's safety during study participation,
   including any of the following:

      - Uncontrolled infection or infection requiring a concurrent parenteral antibiotic

      - Uncontrolled diabetes

      - Congestive heart failure

      - Myocardial infarction within the past 6 months

      - Chronic renal disease

      - Coagulopathy (excluding prophylactic anticoagulation)

   - Known human immunodeficiency virus (HIV) positivity, hepatitis B surface
   antigen-positivity, or hepatitis C positivity with abnormal liver function tests

PRIOR CONCURRENT THERAPY:

Inclusion criteria:

   - See Disease Characteristics

   - No concurrent prophylactic growth factors (filgrastim [G-CSF] or sargramostim
   [GM-CSF]) during course 1 of study treatment

Exclusion criteria:

   - More than one prior chemotherapy regimen for SCLC

   - Less than 24 hours from any prior radiotherapy or the likelihood of toxicity from
   prior radiotherapy

   - Radiotherapy to > 25% of the bone marrow within the past 4 weeks

   - Less than four weeks since major surgery