Abstract
In recent years, immune checkpoint blockade (ICB) therapy has become an important treatment strategy for gastrointestinal tumors, however, it only benefits about 1/3 of patients. Since the microbiome has been shown to play an important role in the human body for a long time, a growing number of studies are focusing on its relationship to ICB therapy in cancer, specifically how intestinal microbes affect the efficacy of immune checkpoint inhibitors (ICIs) therapy in patients. On this basis, probiotic interventions, fecal microbiota transplantation (FMT), dietary interventions, and other methods which improve or maintain the structure of the intestinal flora have attracted widespread attention. This article discusses the four aspects of the microbiome, ICB, combined treatment of gastrointestinal tumors, and regulation of gut microbiome. Particularly, the discussion focuses on the contribution of probiotic intervention in improving the therapeutic effect of ICIs to prolong the survival time of patients and reduce the severity of immune-related adverse effects (irAEs).