Clinical analysis of gastrointestinal stromal tumor: a report of 539 cases

Objective To investigate the clinicopathological characters of primary gastrointestinal stromal tumor (GIST), and to analyze the influencing factors on the prognosis of patients. Methods The clinical data of 539 patients with primary GIST who were admitted to the Southwest Hospital of Third Military Medical University from January 2002 to　December 2012 were retrospectively analyzed. The treatment methods were selected based on the principle of　complete resection of tumor without severely influencing the function of related organs, and in combination with the condition of patients and the position of GIST. The method of adjuvant therapy was selected according to the modified National Institite of Health (NIH) risk stratifications. All the patients were followed up till February 2013 via outpatient re　examination, letter or telephone. The survival rate was calculated using the KaplanMeier method. The univariate and multivariate analysis of the relationship between clinicopathological  factors and the prognosis of GIST patients were done using the Log－rank test and COX regression model, respectively. Results The age of GIST onset was concentrated between 40 and 70 years, which accounted for 76.25%(411/539).  The tumor sites included stomach (316 cases), small intestine (100 cases), esophagus (37 cases), abdomen (37 cases), colon and rectum (26 cases) and pelvic cavity (23 cases). Four hundred and sixtyseven patients received surgical treatment, and 72 received non　surgical treatment. The positive rates of CD117, CD34, α smooth muscle actin, S100 were 91.65%(428/467), 86.30%(403/467), 36.18%(106/293) and 9.78%(18/184), respectively. A total of 396 patients were followed up with a median time of 29 months (range, 2~94 months). The 1, 3, 5year overall survival rates were 97.4%, 78.7%, 60.0%. The results of univariate analysis showed that tumor diameter, radical resection, modified NIH risk stratification and mitotic index were correlated with the survival rates of GIST patients (χ²=69.846, 9.776, 67.368, 49.041, P<0.05). The results of multivariate analysis showed that radical resection and modified NIH risk stratification were the independent prognostic factor for patients with GIST (RR=2.493, 2.330, P<0.05). Conclusion Radical resection and modified NIH risk stratification are the independent prognostic factors for patients with GIST, and operation is the main treatment method for GIST.