Risk factors for malignant evolution of gastrointestinal stromal tumors

Gastrointestinal stromal tumors are the most frequent non-epithelial digestive tumors, being classified in the group of primitive mesenchymal tumors of the digestive tract. These tumors have a non predictable evolution and where stratified regarding the risk for malignant behavior in 4 categories: very low risk, low risk, intermediate risk and high risk. We performed a retrospective non randomised study including the patients with gastrointestinal stromal tumors treated in the Department of General Surgery and Liver Transplantation of Fundeni Clinical Institute in the period January 2002 - June 2007, to define the epidemiological, clinico-paraclinical, histological and especially evolutive features of the gastrointestinal stromal tumors from this group, with a special regard to the risk factors for their malignant behavior. The most important risk factors in gastrointestinal stromal tumors are the tumor size and the mitotic index, based on them being realised the classification of Fletcher in the 4 risk categories mentioned above. In our group all the local advanced or metastatic gastrointestinal stromal tumors, regardless of their location, were classified in the group of high risk for the malignant behavior. The gastric location and the epithelioid type were positive prognostic factors, and the complete resection of the tumor, an other important positive prognostic feature, was possible in about 80% of the cases, probably because the gastrointestinal stromal tumors in our study were diagnosed in less advanced evolutive situations, only about one third being metastatic and about 14% being locally advanced at the time of diagnose. The association with other neoplasias was in our cases insignificant, only 5% of the patients presenting concomitant malignant digestive tumors and 7.6% intraabdominal benign tumors. Gastrointestinal stromal tumors remain a challenge for the medical staff, regarding their diagnose and therapeutical management, the stratification of the risk for their malignant behavior being essential for the evolution of these patients.