RATIONALE: Imatinib mesylate may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth.

PURPOSE: This phase II trial is studying the side effects of imatinib mesylate and to see how well it works in treating patients with liver metastasis from a gastrointestinal stromal tumor.

OBJECTIVES:

• To evaluate the safety and efficacy of imatinib mesylate in patients with resectable hepatic metastasis secondary to gastrointestinal stromal tumor.

OUTLINE: This is a multicenter study.

Patients receive oral imatinib mesylate daily. Treatment continues in the absence of disease progression or unacceptable toxicity.

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