Imatinib Mesylate in Treating Patients With Liver Metastasis From a Gastrointestinal Stromal Tumor

DISEASE CHARACTERISTICS: * Diagnosis of gastrointestinal stromal tumor (GIST) * Hepatic metastasis meeting the following criteria: * No more than 3 hepatic metastases * Clinically diagnosed as surgically resectable with no macroscopic residual tumor * Synchronous hepatic metastasis allowed provided primary tumor is also resectable * No metastatic tumor that requires radiofrequency ablation and/or microwave coagulation therapy to control the disease * No extrahepatic metastasis * No history of GIST recurrence PATIENT CHARACTERISTICS: * ECOG performance status 0-1 * Leukocyte count ≥ 3,000/μL * Neutrophil count ≥ 1,500/μL * Hemoglobin ≥ 8.0 g/dL * Platelet count ≥ 75,000/μL * Total bilirubin ≤ 2.0 mg/dL * ALT and AST \< 120 IU/L * GTP \< 210 IU/L * Not pregnant * No poorly controlled diabetes mellitus * No NYHA class III-IV cardiac function * No hepatitis B or hepatitis B carriers * No other malignancy requiring treatment PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No prior imatinib mesylate * No prior interventional radiology for metastatic disease * No other concurrent treatment, including surgery or radiotherapy, for metastatic lesions