The Prevention and Treatment of Radiation and Chemotherapy-Induced Intestinal Mucositis

Gut microbiota and cancer therapy share an intimate and dynamically connected relationship. The mucosa lining the gastrointestinal (GI) tract forms a selective barrier between ourselves and the external environment. From mouth to rectum, cytotoxic cancer therapy (radiation and chemotherapy) can lead to dysfunction and disruption of this mucosal lining with a pathophysiology involving epithelial and endothelial cell death as well as activation of the mucosal immune system. The symptoms of mucositis, the clinical term for this condition include abdominal pain, nausea, vomiting, and diarrhea. Radiation and chemotherapy-induced mucositis is a frequent and major dose limiting side effect of cancer therapy. In practice, there is currently no therapy that successfully prevents or treats mucositis. However, therapeutic manipulation of gut microbiota or harnessing the biologic effects of microbial products may hold the key to mucositis prevention and treatment. Recent advances also indicate that beneficial commensals and probiotic bacteria have the potential to dramatically enhance the antitumor effects of cytotoxic therapies as well as immune checkpoint inhibitors.