DISEASE CHARACTERISTICS: Histologically proven unresectable locally advanced or metastatic adenocarcinoma of the stomach or gastroesophageal junction Limited prior immunotherapy or chemotherapy OR Failure after no more than 1 prior regimen of immunotherapy or chemotherapy (including chemotherapy as radiosensitizer) Primarily resistant or responsive disease but with subsequent progression No osseous metastasis as only site of disease Bidimensionally measurable or evaluable disease Mediastinal or hilar lymph nodes must be at least 1.5 cm in diameter by CT or MRI scan to be considered measurable No brain metastases