Antibiotics and immunotherapy in gastrointestinal tumors: Friend or foe?

Abstract

The incidence of gastrointestinal (GI) tumors is increasing year by year, and its pathogenesis is closely related to the intestinal flora. At present, the use of antibiotics is very common in the clinic. And cancer patients with low immunity are vulnerable to all sorts of infections, such as respiratory tract infections and urinary tract infections. Moreover, cancer patients easily run into fever and neutropenia induced by myelosuppression. Therefore, antibiotics are used extensively and even overused in many conditions. However, because of the special anatomical location of the gastrointestinal tract, the antibiotic usage will bring changes to the intestinal flora. Besides, with the expanding popularity of immunotherapy, various factors affecting the efficacy of immune checkpoint inhibitors (ICIs) have been extensively explored, including cancer-associated inflammation and the local and systemic factors that lead to immunosuppression. Some biomarkers for ICIs, including the expression of PD-L1, tumor mutation load, and microbiota, also have been investigated, and many studies have confirmed that gut microbiota can affect the efficacy of immunotherapy. But further studies on the influence of antibiotics directly on immunotherapy are rare. In this review, we discuss the relationship between GI tumors and antibiotics, the current status of immunotherapy in GI tumors, and the influence of antibiotics on immunotherapy.

Global research trends on the links between the gut microbiome and cancer: a visualization analysis

“…The blue terms emerged first, followed by the yellow and green terms that appeared later Furthermore, the increase in the number of publications on microbiota and cancer may be linked to many hot topics published during this time frame, exposing innovative theories that lead to new fields of research. These findings suggest new therapeutic and diagnostic concepts for various disorders in the field of oncology [38][39][40][41][42][43][44][45][46][47][69][70][71][72][73] such as "effect of probiotics on cancer", "microbiota composition and gene expression" and "hostmicrobiome interaction in cancer immunotherapy".…”

Is the survival of patients treated with ipilimumab affected by antibiotics? An analysis of 1585 patients from the French National hospital discharge summary database (PMSI)

“…[11][12][13] From 2017 onwards, several retrospective and prospective clinical studies then evaluated the association between antibiotics and the efficacy of immunotherapy. [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] All of these studies showed significantly worse progression-free and/or overall survival in the group of patients exposed to antibiotics. The relative decrease in median overall survival ranged from 3.8 to 16.7 months.…”

Gut microbiome and its role in colorectal cancer

“…The data from these small perspective studies can be extrapolated into immunotherapy treatment of microsatellite instability–high CRC patients because there are no data on this association from any known perspective analysis. In a retrospective analysis including different gastrointestinal cancers, such as CRC, Yan et al found that antibiotics adversely affect the gut microbiome and influence the development and progression of cancer, especially CRC [ 52 ]. Different strains of bacteria are connected to different gastrointestinal (GI) tumours; for example, enterotoxigenic Bacteroides fragilis is connected to CRC [ 53 , 54 ].…”

“…Different strains of bacteria are connected to different gastrointestinal (GI) tumours; for example, enterotoxigenic Bacteroides fragilis is connected to CRC [ 53 , 54 ]. Previous studies have shown the correlation between the efficiency of immunotherapy and the abundance of these specific strains of bacteria, such as Bifidobacterium longum or Ruminococcaceae bacteria [ 52 – 54 ]. Thus, it is possible to influence immunotherapy responsiveness by manipulating gut microbiota.…”