Systematic review of the literature
Figure 1 shows the flow diagram of the study selection [10]. All the included published studies were randomized and placebo-controlled in design and were in accordance with the inclusion criteria of the present study for patients with refractory metastatic colorectal cancer (mCRC). A systematic review of the published literature initially identified 767 potential publications. Following removal of meeting abstracts, duplicated publications, and studies that were not randomized placebo-controlled trials, the final publications were read and reviewed in full by the investigators.
Five published clinical trials, which included 2,604 patients with refractory mCRC, were considered eligible for meta-analysis [4–7,11]. The published studies included: the CORRECT Trial, of regorafenib monotherapy for previously treated mCRC [4]; the RECOURSE Trial, of TAS-102 for refractory mCRC [5]; the TERRA phase III trial, of trifluridine/tipiracil (TAS-102) monotherapy in Asian patients with previously treated mCRC [6]; the FRESCO Trial, of the effect of fruquintinib compared with placebo on overall survival (OS) in patients with previously treated mCRC [7]; the CONCUR trial, of regorafenib plus best supportive care versus placebo in Asian patients with previously treated mCRC [11].