Assessment of probiotic and prebiotic use in gynecologic cancer patients: a systematic review

Objective To evaluate evidence on the impact of probiotics and prebiotics on clinical outcomes, treatment efficacy, quality of life, safety, and translational endpoints in patients with gynecologic cancers. Data sources A systematic search of PubMed, Embase, and Scopus was conducted in March 2023 and updated through September 2025. Gray literature sources (ClinicalTrials.gov , reference lists) were also reviewed. Study eligibility criteria Eligible studies included randomized controlled trials and prospective interventional studies in women with gynecologic cancers (cervical, endometrial, ovarian, uterine, and vulvar) undergoing treatment. Interventions were probiotic, prebiotic, or dietary fiber supplementation. Eligible outcomes included treatment toxicity, stool consistency, quality of life, postoperative outcomes, oncologic outcomes, safety, and microbiome endpoints. Exclusions were retrospective studies, case reports, reviews, conference abstracts, and studies without cancer-related outcomes. Study appraisal and synthesis methods Three independent reviewers screened studies using Covidence, with disagreements resolved by consensus or adjudication. Risk of bias was assessed with the Cochrane Risk of Bias 2.0 tool. Due to heterogeneity in strains, dosing, and outcomes, structured narrative synthesis was conducted rather than meta-analysis. Results From 2308 screened records, 9 randomized controlled trials involving 663 patients were included. Seven studies evaluated probiotics and 2 assessed prebiotics/fiber. Most focused on radiation-induced toxicity in cervical (n=415) and endometrial cancer (n=170) patients. Probiotics significantly reduced incidence and severity of radiation-induced diarrhea, improved stool consistency, and decreased antidiarrheal use (P <.05). Prebiotics alone showed minimal benefit. One perioperative study found probiotics accelerated bowel recovery and reduced postoperative complications. Three translational studies showed probiotics reduced gut permeability but did not alter microbial composition. No trials examined chemotherapy or immunotherapy outcomes, progression-free survival, or overall survival. Adverse events were infrequent and no major safety concerns were identified. Conclusion Probiotic supplementation demonstrates consistent benefit in reducing radiation-induced gastrointestinal toxicity in gynecologic cancer patients, while prebiotics alone show limited efficacy. Evidence gaps include effects on chemotherapy, immunotherapy, oncologic outcomes, and survival. Heterogeneity in formulations limits clinical applicability, and standardized strain-specific trials are needed. Future research should evaluate long-term oncologic outcomes, optimize microbiome-directed interventions, and establish safety in immunocompromised populations.