Survival and prognostic factors analysis in surgically resected gastrointestinal stromal tumor patients.

Background/aims: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the digestive tract and predicting the clinical behavior and prognosis of GISTs has still been problem for both pathologists and clinicians. The aim of this study was to investigate the survival and prognostic factors of gastrointestinal stromal tumors after surgery.

Methodology: Hematoxylin and eosin (H&E) stained histopathological slides of tumors from patients with GISTs were reviewed. Immunohistochemical staining was performed to demonstrate CD117, CD34, platelet -derived growth factor receptor (PDGFR-alpha) and Ki-67 protein expression. Clinicopathologic features (age, sex, tumor location and size, cell type, mitotic count, risk category, necrosis, surgical method, expression of CD117, CD34, PDGFR-alpha and Ki-67 protein) were evaluated by univariate and multivariate analyses in 135 patients with resected primary GISTs to identify independent prognostic factors.

Results: The overall disease-specific survival of 135 patients was 94.1% at 1 year, 76.3% at 3 years and 65.9% at 5 years. Multivariate analyses indicated that the tumor size, primary location, mitotic count, risk category, necrosis and Ki-67 index were independent significant predictors of survival (p < 0.05). Ki-67 index was strong poor predictors of survival as tumor size and mitotic count.

Conclusions: Fletcher's biological behavior ranking method was a good approach to predict prognosis of GIST patients and had significant clinical value. It's better to combine other factors such as Ki-67 index and tumor primary location et al to predict prognosis accurately. Accurate prognostic prediction could provide evidence for postoperative adjuvant targeted therapy.