Gastrointestinal Stromal Tumors

Abstract

Gastrointestinal Stromal Tumors (GISTs) are non-epithelial, non-myogenic, non-neurogenic, and non-lymphogenic GIT neoplasms built of spindle and/or epithelioid cells with the expression of c-kit proteins. Histogenesis is still unclear, criteria of malignancies are not adopted, biological behavior is not known, and the diagnosis and prognosis are questionable. The aim of the paper was to create clearer conclusions about the diagnosis, prognosis and treatment of GIST, upon the analysis of numerous cases.On the basis of multifaceted search of Medline, Index Medicus and cited references, published articles were collected, in all languages, from the first published case in 1984 until the end of 2000. The analysis of 98% published articles with 2088 (99%) GIST cases was performed. After quantitative synthesis, qualitative analysis was obtained by statistical data processing.GISTs were represented in 1-4% of gastrointestinal tract (GIT) tumors, and they were most frequently (42%) nonepithelial GIT tumors. GIST (n = 1368) were most frequently located on the stomach (53%) then on the small intestine (27%), rectum (4%) and on the colon, duodenum, esophagus, retroperitoneum, mesenterium and omentum (2-3%). Histopathologic, imunohistochemical, and prognostic differences were significantly dependent on GIST localization. GIST (n = 1040) were equally present in males and females, but GIST of the small intestine was more frequently found in females. The average age of patients was 62 years. Symptomatology of GIST was nonspecific and one third of patients were asymptomatic. Imuno-histochemical investigations (n = 1492) were necessary for the correct GIST diagnosis, and they were positive on: vimentin in 98%, CD117 in 90%, CD34 in 65%, NSE in 58%, S-100 in 21%, SMA in 33% and desmin in 8% of cases. About 55% of GIST had malignant behavior. At the moment of operative treatment, 20% of patients had liver and/or peritoneal metastases. Metastatic dissemination of GIST was not lymphatic. Prognosis of malignant GIST was significantly poorer compared to the other GIT sarcomas. The most significant clinical parameters of the disease behavior were tumor size and mitotic activity, and significant were: tumor localization, hemorrhage and necrosis in the tumor, cellularity, mucosal invasion, and cellular and nuclear atypia. In spite of all criteria, even the most benign GIST could relapse with metastases. Even the incomplete resection as well as the resection of recurrent tumor had enabled better survival rate.According to this analysis GIST were the most frequent stromal GIT tumors. Correct diagnosis of GIST was based on imunohistochemical studies, and biological behavior upon the clinico-pathological parameters in 90% of cases. Complete surgical resection was the only therapeutic option. Regional lymphadenectomy was not necessary. Long-term follow-up of these patients was necessary due to the high incidence of recurrence.