Neoadjuvant on the gastroenteropancreatic neuroendocrine tumors: A Systematic Review and Meta-analysis

Background: Clinical value of neoadjuvant therapy has been proven in many malignancies. With a low prevalence of neuroendocrine tumors, the survival benefits of neoadjuvant therapy in gastroenteropancreatic neuroendocrine tumors (GEP-NET) are still unclear based on the up-to-date literature. Aim To assess the effectiveness of neoadjuvant therapy on GEP-NET. Methods Articles were searched electrically on PubMed, Embase, Cochrane Central Register of Controlled Trials, Web of Science, ClinicalTrials.gov and China National Knowledge from inception to 30th June 2020. The survival benefit was assessed by Hard ratio (HR) for overall survival (OS). Median OS, progression-free survival (PFS) and complications were also compared. Results This meta-analysis eventually included eight studies with a total of 457 patients. The overall survival of GEP-NET patients in the neoadjuvant therapy group was improved significantly (HR = 0.52; 95% confidence interval, 0.41–0.66; P  = 0.008). There was a dramatic improvement in OS (5-year OS 65.25% vs. 46.79% P  < 0.001) and PFS (5-year PFS 30.64% VS 14.46%, P  = 0.04) in the neoadjuvant therapy group. There was no difference in the postoperative complications among the two groups ( P  = 0.52). Conclusions Patients with operable GEP-NETs can achieve a significant improvement in overall survival with neoadjuvant therapy. Further large randomized clinical trials are expected to confirm the results.