الفهرس 
Interstitial Cellls of CajalOnly 14 pages are availabe for public view
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Abstract
GISTs represent a heterogeneous group of neoplasms that substantially differ in disease pathogenesis with consequences for tumor progression and clinical outcome. Heterogeneity in GISTs might not only be influenced by molecular, but also non-genetic factors such as age, gender and tumor site. Our understanding of GISTs has been transformed by the landmark discovery of the central role of molecular oncogenic mutations in the pathogenesis, diagnosis and management. All GISTs have the potential for aggressive behavior. The diagnosis of GIST should be considered whenever an intramural mass in a submucosal location is seen in the stomach or small intestine. Mutational status, mitotic index, size and location of the tumour are the most informative criteria for the choice of treatment strategy. Multidisciplinary teams (including surgeons, imagists, pathologists, oncologists) are best suited for GIST patient management. Surgery is the best treatment for localized disease. Histopathology report must offer, besides diagnosis, prognostic factors that are essential for the outcome of the patient. The recurrence rate related to the unpredictable behavior of gastrointestinal stromal tumors (GISTs) continues to be a major topic of investigation since no actual risk evaluation scales have proven to be exceedingly effective in predicting prognosis. We therefore focused in this study on evaluating the prognostic factors influencing tumor recurrence and survival after curative resection of primary gastrointestinal stromal tumors. Our prospective study was conducted on Thirty Seven patients with localized primary GIST who were operated on in the Department of General Surgery. Then completed adjuvant therapy in the medical Oncology Department, Faculty of Medicine; Tanta University Hospital, from March 2016 to August 2017. Patients were staged preoperatively through EUS and abdominal CT. Our surgical approach was based on preoperative investigations, and was determined by tumor size, location and growth character (exophytic or endophytic). Intra operative frozen section was done in all cases to confirm diagnosis and report on margins of excised parts. Then, the mass was sent for histopatholigical examination and immunohistochemistry study for c-kit for good choice of proper line of TKI. Adjuvant imatinib prescribed for every patient for one year in a dose of 400 mg / day orally. Patients were followed postoperatively at 6 months intervals till the end of study for any complaints, complications and local recurrence of tumor or distant metastasis. Based on follow-up data, this study determined the prognostic impact of age, gender, performance status of patients, tumor size, mitotic count, necrosis, mucosal ulceration, location of tumors and type of operation. During follow up period recurrence of GISTs occurred in four patients (10.4%). Time to recurrence ranged from 15 months to 24 months. All cases of recurrence have performance status ˃ 1, tumor size ˃ 10 cm and mitotic index of tumor ˃ 5/50 HPF. In our study; age of patients, gender, tumor necrosis, mucosal ulceration and type of operation are not related to outcome of GISTs. Also, we did not find the site of the GISTs to be significantly related to prognosis of GISTs. We found that the tumor size, the mitotic index of tumor and performance status of patients were the strongest predictive factors.