Clinical And Pathological Evaluation Of Preoperative Adjuvant Imatinib Therapy In GIST

Objective To evaluate the influencing factors associated with preoperative imatinib mesylate(IM)in patients,received preoperative preoperative adjuvant therapy with imatinib mesylate(IM),with unresectable or locally advanced primary gastrointestinal stromal tumor(GIST)and the correlations between the Pathological response and clinicopathologic features.To explore the influence of pathological response on prognosis of patients received preoperative imatinib mesylate therapy for gastrointestinal stromal tumor which could be helpful for guidance of medication and therapy individually.Methods We retrospectively analyzed the clinicopathologic data from consecutive 44 cases of gastrointestinal stromal tumor received preoperative imatinib mesylate,with subsequent treated by stone operation between June 2011 to November 2016 in our clinical department.44 patients were regularly taken imatinib mesylate 400g/day before surgery and the Choi efficacy evaluation criteria was used to evaluate whether the surgical indications were met.All surgical specimens were evaluated by two different senior urological pathologists with at least 5 years of working experience.The pathological features such as fibrous tissues,necrosis or cystic changes were used as evidence for tumor regression and the percentage of the tumor area was taken as the degree of postoperative pathological response.Univariate and multivariate COX regression analyses were used to determine the prognostic factors for patients with gastrointestinal stromal tumor.Correlation analysis methods were used to evaluate the relationship between pathological response and clinical pathological factors.The optimal threshold was obtained by using receiver operating characteristic curve plotting for pathological response to being classified into two groups.Kaplan-Meier survival curve and Log-rank method were used to analyze the relationship between pathological response and prognosis.Results Univariate COX regression analyses revealed that the surgical type,tumor size,Ki67,risk grade and tumor response were associated with 3-year recurrence-free survival(RFS)and overall survival(OS)(P<0.05);Multivariate COX regression analyses showed that pathological response and Ki67 prognosis were independent risk factors(P<0.05).Correlation analysis showed that there was significant difference between the pathological response and Ki67,mitotic figures,surgical categories and surgical methods(P<0.05).The area under the ROC curve of pathological response was 0.850 and the optimal threshold was 40%.A total of 44 patients were classified into two groups according to the pathological response: high pathological response group(pathological response>40%)and low pathological response group(pathological response≤40%);Kaplan-Meier method and Log-rank test analysis showed that the prognosis of patients with high pathological response group was significantly better than low pathological response group(P<0.05).Conclusion Postoperative pathological response degree and Ki67 are independent risk factors for postoperative prognosis of GIST patients after preoperative adjuvant therapy.The postoperative pathological response is classified with 40% as the optimal threshold.The prognosis of the high response rate group(>40%)is significantly better than that of the low response rate group(≤40%),which plays an important role in evaluating the efficacy of preoperative adjuvant therapy and better guides the choice of postoperative treatment strategies.