Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed recurrent small cell lung cancer (SCLC)
after platinum-containing chemotherapy regimen with or without thoracic radiotherapy

- Limited stage or extensive stage SCLC

- Measurable disease

- At least 20 mm by conventional techniques OR

- At least 10 mm with spiral CT scan

- No pleural effusions, bone metastases, brain metastases, or abnormal radionucleotide
scans as sole evidence of disease

- No symptomatic or uncontrolled brain or leptomeningeal disease

- Previously treated brain metastases allowed if neurologically stable

PATIENT CHARACTERISTICS:

Age:

- 18 and over

Performance status:

- Zubrod 0-2

Hematopoietic:

- WBC at least 2,500/mm^3

- Platelet count at least 70,000/mm^3

Hepatic:

- Bilirubin no greater than 1.5 mg/dL

- SGOT no greater than 2 times upper limit of normal

Renal:

- Creatinine no greater than 1.5 mg/dL OR

- Creatinine clearance at least 60 mL/min

Cardiovascular:

- No symptomatic heart disease

- No myocardial infarction within the past 6 months

Other:

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception for 1 month before, during, and for
2 months after study

- No pre-existing retinal degenerative disease (e.g., retinitis pigmentosa or
associated disorders)

- No other serious concurrent illness

- No other malignancy within the past 5 years except localized nonmelanoma skin cancer
or carcinoma in situ

PRIOR CONCURRENT THERAPY:

Chemotherapy:

- At least 3 weeks since prior chemotherapy

- No more than 2 prior chemotherapy regimens

Endocrine therapy:

- Concurrent steroids allowed at stable dose

Radiotherapy:

- No prior radiotherapy to study lesions

Other:

- At least 3 weeks since prior systemic retinoid or carotenoid therapy

- No concurrent anticonvulsants