DISEASE CHARACTERISTICS: Histologically confirmed invasive, recurrent, or metastatic thymoma or thymic carcinoma not amenable to potentially curative therapy Must have extensive disease defined as: - distant disease - pleural disease with or without mediastinal involvement - recurrent progressive disease in site of previous radiotherapy Measurable disease with at least one bidimensionally measurable lesion Must have octreotide scan prestudy that demonstrates activity in the area of measurable disease within 6 months prior to registration