Abstract
Modern cancer therapy is effective at reducing tumor burden and extending lifespan. However, cancer therapy also induces various gastrointestinal (GI) side-effects that are dose-limiting, reduce quality of life, and potentially lead to treatment failure. Standard medical nutrition therapy for patients undergoing cancer treatment focuses on preventing weight loss and malnutrition but not reducing GI symptoms. Therefore, the objective of this study was to assess efficacy of nutrition therapy to reduce GI side-effects during cancer treatment via systematic review and meta-analysis. A systematic search was conducted in Scopus and PubMed databases. A meta-analysis was performed on articles meeting inclusion criteria to estimate the pooled effect size on GI symptoms, separated by nutrition intervention type (nutrient supplementation, oral nutrition supplement, or dietary counseling). Further subgroup analyses were conducted based on cancer type, cancer therapy, and nutrient intervention. All statistical analyses were performed in Stata/MP version 17.0 using 2-sided tests with P < 0.05 as the threshold for statistical significance. A total of 15,556 articles were captured by the search algorithm, and 139 studies met inclusion criteria for meta-analysis. Articles reported 12 different GI symptoms, resulting in 151 total meta-analyses across symptom, cancer treatment, and nutrition intervention subtypes. Meta analyses indicated that collectively (all interventions combined), nutrient supplementation reduced nausea, vomiting, and diarrhea incidence (all P < 0.001). Oral nutrition supplements had no effects on GI symptoms (all P > 0.05). Dietary counseling reduced constipation and diarrhea incidence. Although 9 individual nutrient supplementation interventions reduced 8 symptoms, probiotic supplementation had some of the strongest effects on abdominal pain, vomiting, and diarrhea incidence. This meta-analysis supports implementation of specific medical nutrition therapies to treat GI symptoms during cancer therapy and identifies those requiring additional investigation. Given the large variation in responses within and across studies, future experiments should explore personalized nutrition-based strategies to optimize treatment efficacy. This study was register at PROSPERO as 549116.