The Clinical And Prognostic Characteristics Of Low-risk Gastrointestinal Stromal Tumors

ObjectiveTo investigate the clinical and prognostic characteristics of low-risk(Modified NIH classification,2008)gastrointestinal stromal tumors(GIST).MethodsClinical characteristics of 205 patients,who received radical operation for low-risk GIST at the First Affiliated Hospital,College of Medicine,Zhejiang University,between January 2002 and December 2012,were retrospectively analyzed.None of the patients received preoperative or adjuvant targeted therapy.ResultsOf all 205 patients,there were 102 men and 103 women.The median age was 56(range 24～85).The most common symptom was gastrointestinal bleeding(N=109,53.2%),followed by abdominal discomfort(N=44,21.5%).GIST located in the stomach in 100 patients(48.8%),duodenum in 34 patients(16.6%),small intestine in 64 patients(31.2%),and colorectum in 7 patients(3.4%).The median tumor size and mitotic index(MI)was 4.0 cm(2.1～5.0 cm),and 2(0～5)/50 high power field(HPF),respectively.Multivariate analysis showed that the MI>2/50 HPF and tumors size>4.0 cm were independent prognostic factors for tumor recurrence,respectively(P<0.05).According to the tumor size and MI,patients were divided into four groups,Group A:MI≤2/50HPF and tumor size≤4.0cm(N=100);Group B:MI≤2/50HPF and tumor size>4.0cm(N=49);Group C:MI>2/50HPF and tumor size≤4.0cm(N=36);Group D:MI>2/50HPF and tumor size>4.0cm(N=20).The median follow-up time was 76 months(13～161 months).The three-year and five-year recurrence free survival(RFS)of patients in group D was both 78.3%,which was worse than the other patients(P<0.05).ConclusionAccording to the low-risk patients evaluated by modified NIH classification,the prognosis of patients with MI higher than 2/50 HPF and tumor size large than 4.0 cm was worse.