Gastrointestinal stroma tumors (GIST) arise from the pacemaker, the interstitial Wells of Cajal. These tumors constitute 1 to 3% of gastrointestinal neoplasms, and may occur in each portion of the gastrointestinal tract. The most useful prognostic factors are tumor size, mitotic index, cell structure and location within the gastrointestinal tract.
<bold>The aim of the study</bold> was to assess the chosen prognostic factors (location in the gastrointestinal tract and mitotic index) in patients with GIST.
<bold>Material and methods.</bold> Between 1989 and 2002, 74 patients (37 men and 37 women) with an average age of 54.9 years (range from 13 to 89 years) were operated for GIST in the Department of Gastrointestinal Surgery. Two- and five-year survival rates during observation were analyzed, as well as the location within the gastrointestinal tract and mitotic index. Based on the intraoperative and postoperative investigations, the tumor size, presence of metastases and histological type of predominant cells were estimated in each patent. Results were subjected to statistics, where p≤0.05 was considered to be significant.
<bold>Results.</bold> Of the 74 patients included in the study, 3 patients (4%) had a primary tumor located in the lower oesophagus, 42 patients (56.8%) in the stomach, 4 patients (5.4%) in the duodenum, and 13 patients (17.6%) had tumors originated from the small intestine. In an additional 12 patients (16.2%), the tumor originated from the large intestine. The most frequent (51%) mitotic index was 2, and 9/50 hpf was considered an intermediate malignant potential risk. Two-year survival was common in patients with GIST located in the oesophagus, stomach, and duodenum, totalling 34 (79%) patients. A lower than two-year survival rate was noted in patients with GIST arising from the small intestine: 7 (63.6%) patients had tumors arising from the colon and 4 (36.3%) patients had rectal tumors. Five-year survival was also the most frequent in patients with GIST located in the upper part of gastrointestinal tract (37.2%), in the median part of gastrointestinal tract (36.3%), and in the lower part of the gastrointestinal tract (27.7%). Correlation between location, mitotic index and survival of patients was assessed. The correlation studies showed a statistically significant influence of tumor location in the gastrointestinal tract (p=0.0264) and mitotic index (p=0.0003) with the survival of patients operated for GIST. Thus, the lower location and higher mitotic index of GIST are associated with shorter survival of patients.
<bold>Conclusions.</bold> The mitotic index and location in the gastrointestinal tract are essential prognostic factors in analyzed patients with GIST. In the analyzed group, the lower locations and higher mitotic indices of GIST were associated with shorter survival of patients.
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