Inclusion Criteria

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