Clinical Analysis Of Prognostic Factors For 102 Patients With Gastrointestinal Stromal Tumor

Objective: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract (GIT),it arises in any portion of the digestive tract,including omentum,peritoneum and mesentery. In 1983,Mazur and Clark carried out retrospective study of the departed mesenchymal tumor of the gastrointestinal tract,they found that the tumor was a kind of un-directional differentiated stromal tumor and designated it as"Gastrointestinal stromal tumor"at first time. The research of etiopathogenisis considered it that the mutation of proto-oncogene c-kit led to sustained activity of protein tyrosine kinase (PTK),which caused cell multiplication out of control. The clinical manifestation was varied. The preoperative diagnosis was difficult. The prognosis was concerned with multiple factors. In recent years,the literatures about GIST were relative more in exterior and interior,but many of them were small samples or individual case,furthermore,the report of prognosis was fewer relatively. Our research analyzed the clinical and pathological characteristics of GIST,investigated prognostic factors to provide valuable information and instruct therapy. Methods: The clinicopathologic and follow-up records of 102 GIST patients were retrospectively analyzed, they were surgically resected at the fourth hospital affiliated Hebei Medical University from July 1996 to June 2007. We constructed the data bank of GIST and analyzed the clinical presentation, tumor characteristics,pathological characteristics and other tests features (such as ultrasound , computed tomography and gastro-endoscopy);meanwhile,we looked up the cases and followed up survival status of these patients by phone and letter,classified two groups by death and survival(or censored). To obtain the independent prognostic factor,we selected twenty clinical and biochemical indexes which maybe affected the prognosis of GIST. At the same time , we enumerated one model to analyze. All statistical analysis was performed by SPSS 10.0 software, the measurement data was analyzed by T test. The survival rates were calculated by Kaplan-Meier method and the prognostic factors were analyzed by univariate log-rank analysis,and Cox proportional hazards model multivariate analysis. Pearson correlation bivariate was used to analyze correlation. p<0.05 was considered statistically significant.Results:1 General document There were 102 patients of GIST who underwent surgical resection and confirmed by pathology from July 1996 to June 2007 including 52 males and 50 females. The age ranged from 14 to 81 years (mean 53.74 years). The size varied from 1cm to 30cm (mean 9.59 cm). Among them,59 cases were in stomach,4 cases were in duodenum,13 cases were in small intestine, 2 cases were in rectum, 11 cases were in peritoneum,5 cases were in mesentery and 8 cases were in omentum. All patients didn't have any preoperative therapy.2 Clinical presentation In 102 cases of GIST,the most common presenting symptom was abdominal gas pain (49.02%),followed by alimentary tract hemorrhage(25.49%). Other manifestations included weight loss (13.73%), anorexia (6.86%), anaemia (1.96%). 30 patients (29.41%) were absence of symptoms.3 Auxiliary examination3.1 CT examination 78 cases of GIST carried out CT examination,significant tumor was observed in 73 out of 78(93.59%). The main characteristics were round or irregular tumors in GIT or abdominal cavity, distinct boundary, adqulis or inhomogeneous enrichment, intimate relationship with GIT, intracavity or expansive growth, sometimes ulceration.3.2 Abdominal ultrasound 35 cases of GIST had ultrasound examination,among them,21 cases could explore the tumor,the positive ratio was 60%. There was no feature of this test,it showed abdominal tumor, clear but no smooth edge and blood-flow signal. Because of the interference of gas, it was not clear to reveal cavitary organ.3.3 Gastro-endoscopy examination The main characteristic of 48 cases of GIST who had gastro-endoscopy test was that the tumor was under the mucous membrane of fundus or body of stomach,the mucous membrane was integrity, lobulated or ulcerative. Among them, 1 case whose tumor arising from lesser omentum had this test and the lesser gastric curvature was compressed,the gastric mucosa was integrated.4 Pathological features4.1 Macroscopic observation The tumor between the GIT grew expansively with elevated mucosa. Some of which were ulcerative. The cut surface was grayish-white or fuscous, we could see bleeding, necrosis and cystis degeneration.4.2 Microscope observation4.2.1 Cellular category GIST was composed of spindle cell and (or) epithelioid cell. The ratio of spindle cell was 87.25% (89/102),while the ratio of epithelioid cell was 12.75% (13/102). The cell of former arrange like braid or palisade with affluent cytoplasm and fusiform nuclear,however, the cell of latter arrange like nidus or chrysanthemum with round nuclear.4.2.2 Mitotic figures In 102 cases of mitosis, 44 cases were less than 5/50HPF, 28 cases were between 5/50HPF and 10/50HPF, 26 cases were more than 10/50HPF.5 Immunohistochemical characteristics In 102 cases,58 cases underwent the immunohistochemical test. 55 cases were defined as positive of CD117;50 cases were defined as positive of CD34,all cases were asystematic distribution.6 Follow-up survival rate The last date was thirtieth,June,2007,the period ranged from 0.60m to 131.30m (mean 24.62 m), the missing rate was 18.63%. The overall 1-,3- and 5-year survival rates were 91.55% , 72.63% and 60.53% respectively. Univariate analysis showed that mitosis,tumor size,surrounding adherence,metastases and ascites were significant prognostic factors ( p<0.05),while age,sex,site,tumor size,weight loss,ulcer,hemorrhage,ectoptygma infiltration,growth category,cellular category,CD117,CD34,Gleevec application , chemotherapy , alpha fetoprotein ,carcino-embryonic antigen didn't affect the prognosis (p>0.05). Cox multivariate analysis indicated that only mitosis and ascites were independent prognostic factors. The relative risks were 3.276 and 4.266 respectively. By correlation analysis,mitosis had positive correlation with prognosis (r=0.474, p<0.05). The mitosis of dead group was higher than that of survival group (p<0.05).Conclusions:1. GIST occurs in middle-aged individuals,the male/ female ratio is about 1:1. The clinical manifestation is lack of specificity, abdominal discomfort and alimentary tract hemorrhage are frequent,some are lack of symptom.2. The main auxiliary examinations of preoperative diagnosis are CT and ultrasound,the gastro-endoscopy test is helpful to the diagnosis of stomach stromal tumor. CD117 and CD34 are worthy to diagnose GIST. 3. Univariate log-rank analysis indicates that mitotic counts,tumor size,surrounding adherence,mitosis and ascites are significant predictors of survival. Multivariate analysis shows that tumor size and ascites are poor prognosis signs. We need regular follow-up post-operation.