OBJECTIVETo identify the clinical pathological characteristics and prognostic factors in patients with gastrointestinal stromal tumors of the stomach.

METHODSThe data of 98 patients of gastric stromal tumors, leiomyomas, leiomyosarcomas, leiomyoblastomas, schwannomas and neurofibromas, collected from Mar. 1983 to Dec. 2001 in our hospital with complete clinical and pathological data, were investigated retrospectively. Gastric stromal tumors were diagnosed by reviewing the tumor slides stained with hematoxylin and eosin (H&E). Two histomorphologically representative areas of each tumor slides were identified and arrayed on a tissue microarray. Immunohistochemistry staining were performed using antibodies to c-kit (CD117), CD34, smooth muscle actin (SMA), Desmin and S-100 proteins. The relations of various clinicopathologic characteristics and outcomes were tested by univariate analysis and multivariate analysis.

RESULTSNinety-one patients were clearly identified as gastric stromal tumors from the 98 patients, who were diagnosed as gastric stromal tumor, leiomyoma, leiomyosarcoma, leiomyoblastoma schwannoma and neurofibroma (92.9%). The follow-up rate was 91% and the median follow up time was 54 months. The patient survival rates at 1, 5 and 10 years were 88.8%, 79.6% and 63.7% respectively. Univariate analysis showed that tumor size, mitotic count, tumor necrosis, nuclear pleomorphism, cell type, cell density, surgical procedure, mucosal invasion, age and lable index of Ki-67 were associated with prognosis (P<0.05). Multivariate analysis showed that tumor size, mitotic count, mucosal invasion and tumor necrosis were predictors of prognosis (P<0.05).

CONCLUSIONTumor size of >10 cm, mitotic count of >10 mitoses per 50 high power fields, necrosis and mucosal invasion are often associated with an aggressive clinical course in gastric stromal tumors.