ABSTRACT
BACKGROUND: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. The GISTs are immunohistochemically defined as KIT (CD117) positive tumors. To evaluate the prognostic factors for GISTs, we investigated the clinicopathological factors and the patient's survival rate. METHODS: Between 1996 and 2002, 37 patients were diagnosed with GIST at Dong-A University Medical Center, and 34 of these patients with localized GIST underwent surgical resection. For the immunohistochemical staining, we used KIT, CD34, s100 and SMA. RESULTS: The primary tumor site was the stomach (60%), and this was followed by small intestine (40%). The most common tumor morphology was spindle cell (83%) followed by epithelial cell (17%). An immunohistochemical analysis revealed that KIT was expressed 100% and CD34 was expressed in 29 cases (78.4%), SMA in 13 patients (35%), and s100 in 7 patients (18.9%). According to the tumor size and mitotic count, 4 patients were classified as very low, 8 were low, 14 were intermediate and 8 patients were high risk. Nine patients (24.3%) underwent adjuvant chemotherapy. The median follow up duration was 29 months. The 5-year disease free survivalrate was 55.1%, and 5-year overall survival rate was 72.8%. The 5-year disease free survival rates for patients with very low and low risk classifications were 100%, and the intermediate risk and high risk were 76.4% and 38.9%, respectively (p=0.1489). The five year overall survival rates for patients with very low and low risk classification were 100%, and intermediate risk and high risk were 90.0% and 0%, respectively (p=0.0179). However, age, pathologic subtype, adjuvant chemotherapy, and immunohistochemical stain results were not significant prognostic factors. CONCLUSION: These results suggest that risk stratification was the most important prognostic factor in GISTs.