Neoadjuvant and Adjuvant Imatinib Mesylate in Treating Patients With Primary or Recurrent Malignant Gastrointestinal Stromal Tumor

You may be eligible if

• Histologically confirmed malignant gastrointestinal stromal tumor
• * Potentially resectable primary disease
• * Potentially resectable recurrent disease
• * Local or intra-abdominal/pelvic metastatic disease
• Documented c-kit (CD117) expression by immunohistochemical analysis of either initial core specimen or, if recurrent disease, from original tumor block
• Primary disease must be visceral, intra-abdominal, or pelvic in origin
• At least 1 unidimensionally measurable lesion
• * At least 5 cm for primary disease
• * At least 2 cm for recurrent disease
• At least 1 viable core biopsy tumor specimen obtained within 8 weeks before registration
• Performance status - Zubrod 0-2
• WBC at least 3,000/mm\^3
• Absolute neutrophil count at least 1,500/mm\^3
• Platelet count at least 100,000/mm\^3
• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• ALT/AST no greater than 2.5 times ULN
• No uncontrolled chronic liver disease
• Creatinine no greater than 1.5 times ULN
• No uncontrolled chronic renal disease
• No New York Heart Association class III or IV cardiac disease
• Must be able to lie still in the PET scanner for approximately 1-2 hours
• No uncontrollable hyperglycemia
• No medical or psychological condition that would preclude study participation
• No severe or uncontrolled medical disease
• No active uncontrolled infection
• No known or suspected hypersensitivity to any component of the study drug
• Any prior malignancy is allowed provided patient remains disease free from that malignancy
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective barrier contraception during and for 3 months after study participation
• At least 28 days since prior biologic therapy
• No concurrent filgrastim (G-CSF) or sargramostim (GM-CSF)
• At least 28 days since prior chemotherapy
• At least 28 days since prior radiotherapy
• See Disease Characteristics
• At least 28 days since prior investigational drugs
• At least 28 days since prior imatinib mesylate
• No concurrent therapeutic doses of warfarin
• Concurrent low-molecular weight heparin or mini-dose warfarin (1 mg per day) prophylaxis is allowed