title: Systematic review: the role of the gut microbiota in chemotherapy- or radiation-induced gastrointestinal mucositis - current evidence and potential clinical applications.
abstract: BACKGROUND
  Gastrointestinal mucositis is defined as inflammation and/or ulcers of the gastrointestinal tract occurring as a complication of chemotherapy and radiation therapy, and affects about 50% of all cancer patients.
  
  
  OBJECTIVE
  To assess the role of gut microbiota in the pathogenesis of gastrointestinal mucositis and the potential for manipulations of the microbiota to prevent and to treat mucositis.
  
  
  METHODS
  Search of the literature published in English using Medline, Scopus and the Cochrane Library, with main search terms 'intestinal microbiota', 'bacteremia', 'mucositis', 'chemotherapy-induced diarrhoea', 'chemotherapy-induced mucositis', 'radiotherapy-induced mucositis'.
  
  
  RESULTS
  The gut microbiota plays a major role in the maintenance of intestinal homoeostasis and integrity. Patients receiving cytotoxic and radiation therapy exhibit marked changes in intestinal microbiota, with most frequently, decrease in Bifidobacterium, Clostridium cluster XIVa, Faecalibacterium prausnitzii, and increase in Enterobacteriaceae and Bacteroides. These modifications may contribute to the development of mucositis, particularly diarrhoea and bacteraemia. The prevention of cancer therapy-induced mucositis by probiotics has been investigated in randomised clinical trials with some promising results. Three of six trials reported a significantly decreased incidence of diarrhoea. One trial reported a decrease in infectious complications.
  
  
  CONCLUSIONS
  The gut microbiota may play a major role in the pathogenesis of mucositis through the modification of intestinal barrier function, innate immunity and intestinal repair mechanisms. Better knowledge of these effects may lead to new therapeutic approaches and to the identification of predictive markers of mucositis.
authors.affiliation: Institut des Maladies de l'Appareil Digestif, Centre Hospitalier Universitaire de Nantes, Nantes, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Touchefeu
authors.forename: E
authors.initials: E
authors.lastname: Montassier
authors.forename: K
authors.initials: K
authors.lastname: Nieman
authors.forename: T
authors.initials: T
authors.lastname: Gastinne
authors.forename: G
authors.initials: G
authors.lastname: Potel
authors.forename: S
authors.initials: S
authors.lastname: Bruley des Varannes
authors.forename: F
authors.initials: F
authors.lastname: Le Vacon
authors.forename: M F
authors.initials: MF
authors.lastname: de La Cochetière
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000009:adverse effects*; D003967:Diarrhea / Q000188:drug therapy / Q000209:etiology / Q000382:microbiology; D006801:Humans; D007410:Intestinal Diseases / Q000188:drug therapy / Q000209:etiology / Q000382:microbiology*; D007422:Intestines / Q000382:microbiology*; D064307:Microbiota; D052016:Mucositis / Q000188:drug therapy / Q000209:etiology / Q000382:microbiology*; D009369:Neoplasms / Q000188:drug therapy / Q000382:microbiology / Q000532:radiotherapy; D019936:Probiotics / Q000627:therapeutic use; D011832:Radiation Injuries / Q000188:drug therapy / Q000382:microbiology*
chemical_list: D000970:Antineoplastic Agents