Surgery for Locally Unresectable Advanced GISTs Without Metastasis After Imatinib Therapy

Inclusion Criteria * Locally advanced unresectable GIST without metastasis at * EC junction requiring total gastrectomy, * Duodenum requiring Whipple operation; * Large GIST requiring multiviceral resection; * Rectum: requiring APR. * Histologically documentation with positive immunostaining for KIT (CD117) * Patient age ≥ 18 years old * ECOG performance status 0 or 1 * Patient must have the following post-operative laboratory values confirmed within 14 days prior to registration: * Creatinine ≤ 1.5 times the institution ULN (upper limit of normal) * WBC ≥ 3,000/mm3 * Platelets ≥ 100,000/mm3 * Total Bilirubin ≤ 1.5 times the institution ULN. NOTE: Patients with elevated bilirubin secondary to Gilbert's disease are eligible to participate in the study. * AST ≤ 2.5 times the institution ULN * ALT ≤ 2.5 times the institution ULN * Female of childbearing potential must have negative serum pregnancy test. -- -NOTE: Post-menopausal women must be amenorrheic for at least 12 months to be deemed not of reproductive potential. * Patient is willing to sign informed consent. Exclusion Criteria * Patient has received post-operative chemotherapy. * Patient has received post-operative radiation therapy. * Patient has received post-operative investigational treatment. * Patient has received prior therapy with imatinib, or any other molecular targeted or biological therapy. * Patient has had an active infection requiring antibiotics within 14 days prior to registrat…