#CANCER THERAPY

Recently, neoadjuvant chemo(radio)therapy [NAC(R)T] is proposed as a new therapeutic strategy for early systemic treatment to increase completeness of resection (R0 rate) and control systemic micrometastases. The newest National Comprehensive Cancer Network (NCCN) guidelines, version 2.2018, recommended NACRT for the management of borderline resectable pancreatic cancer (BRPC). Also, NACRT is considered to be used in high-risk resectable pancreatic cancer (PRC). However, the recommendation of NCCN guidelines lacks high quality evidence. It is controversial for the application of NAC(R)T to RPC or BRPC in the real world, particularly in RPC, which is still intensely discussed at the European Society for Medical Oncology (EMSO) World Congress on Gastrointestinal Cancer 2019. Although there are several randomized controlled trials (RCTs) indicating NACRT increases survival in resectable or borderline resectable PDAC, the trials are limited by small sample sizes. It is still necessary to pool the existing studies to perform a meta-analysis. Indeed, some scholars have done relevant meta-analyses, but most of them are single-arm meta-analyses, such as a recent meta-analysis by Versteijne et al. that lack direct comparison and ignore interstudy heterogeneity. Other published meta-analyses did not focus on survival benefits. Additionally, it is a fact that the definition of RPC and BRPC has undergone several changes over time, which leads to the existence of mixture of RPC and BRPC in the population of included studies according to current standard of resectability status. From this point of view, interstudy heterogeneity exists in all previous meta-analyses.