Clinical Research Of Gastrointestinal Stromal Tumors (GISTs)

Background:Gastrointestinal stromal tumors(GISTs),a kind of rare tumor,take 1～3%of all tumors in digestive tract,but represent the most common mesenchymal tumor of the digestive tract.Since 1983,when Mazur and his colleagues distinguished GISTs from leiomyoma and leiomyosarcoma for the first time,our understanding of GISTs have dramatically improved as Hirota found the acquired mutation of c-kit,which is now thought to be the basic character of GISTs.Imatinib has been considered as a new effective treatment for GISTs since 2002.But GIST still troubled surgeons because it is lack of typical symptom and recurrence is very common.Besides,there is no consensus of risk factors because different researchers have different results.Objective:To investigate the clinical characters,surgical management and prognosis factors of patients diagnosed as GIST from 1999 to 2006 in Huashan Hospital.Method:Collect all cases of operated GISTs with pathological evidence between November 1999 and December 2006 and follow up by telephone and letters.Gender, age,clinical manifestations,locations of tumors,surgical method,lymphadenectomy, immunophenotype,and Fletcher classification are analyzed to identify factors that predict survival rate.All data were analyzed by SPSS13.0.Survival curve was drawed by Kaplan-Meier method.The univariate analysis was done by Log-Rank test and multivariate analysis was done by Cox regression.The level of significance was set at P＜0.05.Results:1.Clinical Features:All 105 cases were diagnosed as GIST,with 49.5%male and 50.5%female.Age ranged from 20～83.31.4%patients presented bleeding of alimentary tract(including haematemesis,melena and anemia),while 24.8%presented abdominal distention or indisposition,14.3%abdominal pain and 29.5%were detected only by physical or assistant examination.The locations of tumors:stomach 53.3%,small intestine 28.57%,colon and rectum 11.43%,post-peritonium 6.67%.Tumor size ranged from 0.5～30cm,with an average of 7.04cm.According to Fletcher classification,Patients were classified as following:very low risk 9.53%,low risk 33.33%,intermediate risk 23.81%,high risk 33.33%。2.Pathological Features:GISTs mainly presented as spindle cells,epithelioid cells or mixture of above the two.In all cases,CD117 and CD34 had been detected.83.8%(88/105) were positive in CD117 and 80%(84/105) were positive in CD34.S-100 and p53 were partially detected.3.Surgical Management:All 105 patients underwent operation.86 underwent radical resection and 19 underwent partial resection.21 patients underwent lymphadenectomy and no metastasis was found in all 111 lymph nodes.4.Follow-up and Results:Follow-up was done by both telephone and letters.85 patients finished the follow-up and 20 were defaulting.The status of patients was recorded as alive or dead. The follow-up ended in November 2007.The univariate analysis showed that locations of tumors,preoperative metastasis, operation type,Fletcher classification predicted a poor prognosis,while multivariate analysis showed preoperative metastasis was the only independent factor that predicted a poor prognosis(P=0.020) and Fletcher classification also might be an indicator though there is no statistical significance(P=0.072) in this research.Conclusion:1.Radical resection is still an important management for GISTs.2.Preoperative metastasis is an independent factor that predicts a poor prognosis.3.Fletcher Classification may be a simple and effective method to predict the prognosis of GISTs.4.Imatinib significantly prolongs life span in recurrence cases,but the results should be confirmed by further studies.