Efficacy and safety of immune checkpoint inhibitors in advanced gastrointestinal cancers: A systematic review and meta-analysis

The use of immune checkpoint inhibitors (ICIs) has changed the paradigm of treating advanced gastrointestinal (GI) cancers; however, their effectiveness and safety characteristics in relation to various cancer subtypes require careful assessment. It is a systematic review and meta-analysis that recombines the existing evidence on ICI therapy outcomes in this diverse patient group. In accordance with PRISMA, four large databases of works published since 2010 were searched. Twenty articles that fit the requirements of the PICO were incorporated. Random-effects models were used to carry out the meta-analyses to pool hazard ratios (HRs) of survival and odds ratios (ORs) of response and safety. It was shown that ICI-based therapies have a significant positive effect on overall survival (HR=0.76, 95% CI: 0.68-0.83), progression-free survival (HR=0.71, 95% CI: 0.65-0.77), objective response rate (OR=2.09, 95% CI: 1.25-2.93), and disease control rate (OR=1.51, 95% CI: 1.23 The most significant gain was recorded in populations that are selected with biomarker, like MSI-H/ dMMR colorectal cancer. Nevertheless, ICIs were also linked with a highly increased likelihood of serious immune-related adverse events (OR=1.64, 95% CI: 1.20-2.07), and the heterogeneity is also great depending on the treatment regimen. Regimens based on ICI have contributed to a very high survival rate in advanced GI tumors with specific biomarkers; however, with more toxicities that need close attention. These results provide the application of ICIs as a routine therapy and highlight the necessity of patient selection based on biomarkers.