DISEASE CHARACTERISTICS:

• Histologically or cytologically proven extensive stage small cell lung cancer, not previously treated with chemotherapy or radiotherapy except for symptomatic brain metastases

• Measurable or evaluable disease

  • Ascites, pleural effusions, osteolytic and osteoblastic bone metastases are not measurable or evaluable

PATIENT CHARACTERISTICS:

Age:

• Over 18

Performance status:

• ECOG 0-3

Life expectancy:

• Not specified

Hematopoietic:

• Platelet count at least 100,000/mm^3
• Absolute neutrophil count at least 2,000/mm^3

Hepatic:

• Bilirubin no greater than 1.25 times upper limit of normal (unless due to liver metastases)

Renal:

• Creatinine clearance at least 60 mL/min

Cardiovascular:

• No cardiac failure or rhythm disturbances requiring medication

Other:

• No history of hypersensitivity to castor oil
• No active uncontrolled infection
• No nonmalignant disease presenting a poor medical risk
• Not pregnant
• Fertile patients must use effective contraception during and for 3 months after the study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• No concurrent immunotherapy

Chemotherapy:

• See Disease Characteristics
• No other concurrent chemotherapy

Endocrine therapy:

• No concurrent hormonal therapy

Radiotherapy:

• See Disease Characteristics
• Palliative radiotherapy allowed (indicator lesion should be outside of irradiated field)

Surgery:

• Not specified