Analysis of Prognostic Factors in Gastrointestinal Stromal Tumors

ABSTRACT

PURPOSE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and are immunohistochemically defined as c-KIT (CD117) positive tumors. This study investigated the behaviors of GISTs of the gastrointestinal tract and determined the prognostic factors associated with GISTs. METHOD: The clinical records of 22 patients, who were diagnosed and underwent surgery for a GIST of the GI tract at Inje university Sanggye Paik hospital from 1998 to 2004, were retrospectively analyzed. The relationship between the disease-free survival rate of the GISTs and several factors including age, gender, mitotic count, tumor site, tumor size, tumor necrosis & hemorrhage, and Ki-67 index was examined. RESULTS: The study group comprised of 13 men and 9 women. The mean age was 57.1 years (31~77 years) at the time of diagnosis. The median follow-up period was 24 months (3~45 months). A complete resection of the tumor was performed in 19 patients. There were lymph node metastases in 1 case. Five out of the 19 patients who had undergone a complete tumor resection showed recurrence (27%). The sites of recurrence were the back (1), liver (1), and abdominal cavity (3). Univariate analysis revealed, the following to be prognostic factors for the disease-free survival of patients with GISTs: high power field mitotic counts of the tumor ( or =5/50; P=0.013), the tumor size ( or =5 cm; P=0.047) and the Ki-67 index ( or =5%; P=0.001). CONCLUSION: The prognostic factors for disease-free survival rate of GISTs were high power field mitotic counts of the tumor, the tumor size and the Ki-67 index. It is recommended that more careful and frequent postoperative follow-up examinations be performed for patients showing the poor prognostic factors.