title: Systematic review: the efficacy of nutritional interventions to counteract acute gastrointestinal toxicity during therapeutic pelvic radiotherapy.
abstract: BACKGROUND
  Radiotherapy-induced damage to noncancerous gastrointestinal mucosa has effects on secretory and absorptive functions and can interfere with normal gastrointestinal physiology. Nutrient absorption and digestion may be compromised. Dietary manipulation is an attractive option for the prevention and management of symptoms.
  
  
  OBJECTIVE
  To synthesise the evidence for the use of elemental formula low- or modified-fat diets, fibre, lactose restriction and probiotics, prebiotics and synbiotics to protect the gastrointestinal tract during pelvic radiotherapy.
  
  
  METHODS
  Four electronic databases were searched. Randomised controlled trials (RCT), controlled trials (CT) and case series in adult patients receiving radiotherapy for pelvic cancers employing nutritional interventions to reduce gastrointestinal toxicity were included. Methodological quality was assessed using a bespoke tool.
  
  
  RESULTS
  Twenty-two original studies (2446 patients) were identified. Study quality was highly variable with only 37% scoring ≥10 points (maximum 17: bespoke scale). Few studies assessed compliance with the intervention. End-points varied and included symptom scales (IBDQ, CTC, Bristol Stool and RTOG). Evidence from RCTs was weak for elemental, low- or modified-fat, fibre and low-lactose interventions with 1/4, 3/4, 1/2, 0/1 trials respectively reporting favourable outcomes. Evidence for probiotics as prophylactic interventions was more promising (4/5 favourable), but dose, strains and methodologies varied.
  
  
  CONCLUSIONS
  There is insufficient high-grade evidence to recommend nutritional intervention during pelvic radiotherapy. Total replacement of diet with elemental formula may be appropriate in severe toxicity. Probiotics offer promise, but cannot be introduced into clinical practice without rigorous safety analysis, not least in immunocompromised patients. The methodological quality of nutritional intervention studies needs to be improved.
authors.affiliation: Department of Nutrition and Dietetics, The Royal Marsden NHS Foundation Trust, Sutton & London, UK.
authors.forename: L J
authors.initials: LJ
authors.lastname: Wedlake
authors.forename: C
authors.initials: C
authors.lastname: Shaw
authors.forename: K
authors.initials: K
authors.lastname: Whelan
authors.forename: H J N
authors.initials: HJ
authors.lastname: Andreyev
mesh_terms: D018752:Diet, Fat-Restricted; D019587:Dietary Supplements; D005247:Feeding Behavior; D005767:Gastrointestinal Diseases / Q000209:etiology / Q000517:prevention & control*; D041981:Gastrointestinal Tract / Q000528:radiation effects*; D006801:Humans; D010386:Pelvic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000209:etiology / Q000517:prevention & control*; D011878:Radiotherapy / Q000009:adverse effects*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome