Gut Microbiome and Its Associations With Acute and Chronic Gastrointestinal Toxicities in Cancer Patients With Pelvic Radiation Therapy: A Systematic Review

• Type of Material: Article
• Authors: Jinbing Bai, Emory University; Zahra A Barandouzi, Emory University; Claire Rowcliffe, Emory University; Rebecca Meador, Emory University; Despina Tsementzi, Emory University; Deborah Bruner, Emory University
• Language: English
• Date: 2021-12-06
• Publisher: FRONTIERS MEDIA SA
• Publication Version: Final Published Version
• Copyright Statement: © 2021 Bai, Barandouzi, Rowcliffe, Meador, Tsementzi and Bruner
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.3389/fonc.2021.745262
• Title of Journal or Parent Work: FRONTIERS IN ONCOLOGY
• Volume: 11
• Start Page: 745262
• End Page: 745262
• Grant/Funding Information: This work was partially supported by the National Institutes of Health/National Institute of Nursing Research (1K99NR017897-01 and 4R00NR017897-03).
• Keywords: PREVENTION; gut microbiome; cancer; DISEASE; Science & Technology; treatment toxicity; PROBIOTICS; ENTERITIS; Oncology; Life Sciences & Biomedicine; gastrointestinal side effects; CHEMORADIATION; pelvic radiation therapy; RADIOTHERAPY
• Research Categories: Health Sciences, Nursing; Health Sciences, Oncology

Abstract

Aim: Pelvic radiation therapy (RT) can impact the gut microbiome in patients with cancer and result in gastrointestinal (GI) toxicities. The purpose of this systematic review was to describe the effects of RT on the gut microbiome and the associations between the gut microbiome and GI toxicities in patients treated with pelvic RT. Methods: PubMed, Embase, and Web of Science databases were searched from their earliest records to August 2020. The articles screening process adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Mixed Method Assessment Tool was used to assess the methodological quality for each included study. All study findings were synthesized and presented in narrative format. Thirteen studies were included. The gut microbiome of fecal samples was analyzed using 16S rRNA sequencing approaches. Results: There were disparities in alpha and beta diversities that existed across the studies. Divergent results were found among various phyla, including Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, Cyanobacteria, Fusobacteria, and Deinococcus-Thermus. Moreover, alteration in the gut microbiome diversity and abundance related to cancer treatment was associated with pelvic toxicities, specifically diarrhea. Following treatment, increases in the abundance of Bacteroides was associated with diarrhea and radiation enteritis. Conclusions: Pelvic RT can disrupt the diversity and abundance of commensal gut microorganisms. A dysbiotic gut microbiome showed a promising association with radiation enteritis through alterations of the intestinal barrier function, innate immunity, and intestinal repair mechanisms; however, confounders, such as diet, were not thoroughly addressed.