In recent years, the relationship between gut microbiota and malignant tumors has been a hot topic. Beneficial gut microbiota microenviroment can promote the efficacy of anti-PD-1-based immunotherapy against epithelial or melanoma, and this efficacy can be achieved by fecal microbiota transplantation. For patients who have received pelvic radiotherapy, gut microbiota composition is significantly changed, and taking probiotics can reduce the radiation-induced toxicities such as diarrhea caused by radiotherapy. The studies have shown that the gut microbiotaof patients who have been given chemotherapy had changed significantly. So improving the related bacteria number can increase the efficacy and tolerance. Balancing the gut microbiome is expected to be a new supportive therapy for the treatment of malignant tumors.

Gut microbiota; Immunotherapy; Radiotherapy; Chemotherapy