DISEASE CHARACTERISTICS: Histologically or cytologically proven recurrent or refractory non-small cell lung cancer Squamous cell Adenocarcinoma (including bronchoalveolar cell) Large cell anaplastic (giant and clear cell carcinomas) Measurable disease (not bone disease only, pleural or pericardial effusions, or irradiated lesions, unless progression is documented after radiotherapy) No CNS metastases