Temozolomide in Treating Patients With Relapsed or Progressive Small Cell Lung Cancer

DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed relapsed or progressive small cell lung cancer

  * Classical or intermediate variant OR
  * Relapsed or progressive extrapulmonary small cell carcinoma of unknown origin
* Bidimensionally measurable disease

  * At least 1 cm by 1 cm by physical exam or radiologic exam
  * Outside prior radiation port unless clinical evidence of disease progression
* Previously radiated brain metastases allowed provided stable or improved

PATIENT CHARACTERISTICS:

Age:

* 18 and over

Performance status:

* ECOG 0-2

Life expectancy:

* More than 12 weeks

Hematopoietic:

* Absolute neutrophil count at least 1,500/mm3
* Platelet count at least 100,000/mm3

Hepatic:

* Bilirubin no greater than 2 times upper limit of normal (ULN)
* SGOT/SGPT no greater than 3 times ULN (5 times ULN if liver metastases present)
* Alkaline phosphatase no greater than 5 times ULN

Renal:

* Creatinine no greater than 2 mg/dL

Other:

* HIV negative
* No AIDS-related illness
* No frequent vomiting or medical condition that would interfere with oral medication administration (e.g., partial bowel obstruction)
* No active nonmalignant systemic disease that would preclude study
* No other active invasive malignancy within the past year or concurrently requiring ongoing treatment
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception for at least 1 month before, during, and for at least 3 months after study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* At least 4 weeks since prior biologic therapy
* No concurrent immunotherapy
* No concurrent biologic therapy
* Concurrent epoetin alfa allowed

Chemotherapy:

* At least 4 weeks since prior chemotherapy
* No more than 1 prior continuous or discontinuous chemotherapy regimen for metastatic disease
* No other concurrent chemotherapy

Endocrine therapy:

* Concurrent hormonal therapy to boost appetite allowed (e.g., corticosteroids or medroxyprogesterone)

Radiotherapy:

* See Disease Characteristics
* At least 4 weeks since prior radiotherapy to 15% or more of bone marrow
* At least 1 week since prior radiotherapy to less than 15% of bone marrow
* No prior radiotherapy to 50% or more of bone marrow
* No concurrent radiotherapy

Surgery:

* Not specified

Other:

* Recovered from prior therapy
* No other concurrent investigational drugs
* Concurrent pamidronate allowed