Benefit of imatinib adjuvant therapy for patients with intermediate risk gastrointestinal stromal tumor: a multi-center retrospective analysis in China

Abstract

Background The benefit of postoperative imatinib therapy on intermediated risk gastrointestinal stromal tumor patients were still under debate. Thus, the present study aims to investigate the impact of imatinib adjuvant therapy on the prognosis of intermediate risk gastrointestinal stromal tumor patients.Methods From January 2000 to April 2018, a total of 450 intermediate risk gastrointestinal stromal tumor patients received R0 resection from eight centers in China were enrolled. The clinicopathological features and prognosis of patients were analyzed. Discrete variables were analyzed using the Chi-square test or Fisher's exact test. Significant predictors for survival identified by univariate analysis and multivariate analysis. Disease-free survival was evaluated by Kaplan-Meier method.Results Among the 450 patients, 109 patients (24.2%) received imatinib treatment. The recurrence rate of patients with and without imatinib treatment was 7.3% and 5.3%, respectively. For the entire cohort, gene mutational status was the only independent risk factor for disease-free survival of patients though univariate and multivariate analysis (P=0.028). For patients without imatinib treatment, tumor location (P=0.025) and gene mutation status (P=0.040) were prognostic factors in univariate analysis. However, only gene mutational status was independent prognostic factor (P=0.037). The disease-free survival of gastrointestinal stromal tumor with exon 11 deletion mutation with and without imatinib treatment were comparable (P=0.531).Conclusions Imatinib adjuvant treatment could not improve the prognosis of intermediate risk gastrointestinal stromal tumors. Intermediate gastrointestinal stromal tumors with exon 11 deletion mutation or non-gastric location may be candidates for imatinib treatment.