Neoadjuvant Imatinib in recurrent/metastatic gastrointestinal stromal tumors: A systematic review and meta-analysis of proportions

Abstract INTRODUCTION Metastatic and recurrent gastrointestinal stromal tumors (GISTs) present challenging clinical management. Imatinib is the standard first-line therapy, improving survival and reducing tumor burden, in the neoadjuvant use, facilitating surgical intervention. This systematic review and meta-analysis assess the efficacy of neoadjuvant imatinib in metastatic/recurrent GISTs, highlighting its potential to enhance surgical outcomes and overall patient management. METHODS A systematic search was conducted in PubMed (end-of-search: 8 October 2024) for records on neoadjuvant imatinib therapy in recurrent/metastatic GISTs. Pooled proportions and 95% confidence intervals were calculated with common-effect and random-effects models. Subgroup and meta-regression analysis were performed, addressing heterogeneity and examining any potential association between the factors that varied, and the outcomes reported. This meta-analysis was performed following PRISMA guidelines. RESULTS The search identified 397 articles, and 13 were analyzed. The meta-analysis of proportions indicated that 2-year and 5-year PFS were 72% (95% CI:53%-86%) and 43% (95% CI:17%-74%), respectively while 2-year and 5-year OS were 85% (95% CI:78%-90%) and 60% (95% CI:51%-68%), respectively. The pooled R0 resection rate was 80% (95% CI:62%-91%), associated positively with that of radiological partial response (β = 3.92,p < 0.001). Further meta-regression analysis yielded no significant association with preoperative imatinib duration. CONCLUSION In this meta-analysis, involving 316 patients included in 13 studies, significant outcomes for the neoadjuvant imatinib therapy of recurrent/metastatic GISTs were observed, as it yielded favorable overall survival rates and high rates of microscopically complete resections. R0 rate was significantly associated with that of radiological partial response, however, it was not associated with the preoperative imatinib duration.