DISEASE CHARACTERISTICS: Histologically proven malignant mesothelioma not amenable to potentially curative radiotherapy or surgery Epithelial, sarcomatoid, or mixed subtype Any site of origin allowed including, but not limited to, the following: Pleura Peritoneum Pericardium Tunica vaginalis Measurable disease At least one lesion accurately measured in at least one dimension Lesion at least 20 mm at largest diameter with conventional techniques or at least 10 mm with spiral CT scan The following are not considered measurable disease: Bone lesions Leptomeningeal disease Ascites Pleural/pericardial effusion Abdominal masses not confirmed and followed by imaging techniques Cystic lesions Tumor lesions located in a previously irradiated area