Effects of exercise on gut microbiota in patients with cancer: a scoping review

Cancer and its treatments, such as chemotherapy, radiotherapy, endocrine therapy, and targeted therapy, often cause systemic effects, including inflammation, immune suppression, metabolic changes, and gastrointestinal toxicity. These complications are increasingly believed to be related to gut microbiota disorders, which play a crucial role in maintaining balance within the human body. In healthy individuals, exercise appears to have a beneficial influence on this microbial community. Yet how it influences the microbiota in cancer patients remains unclear.

This scoping review aimed to summarize the current observational evidence on the relationship between exercise and gut microbiota in individuals with cancer. The focus was on microbial diversity, bacterial composition, and research gaps in the current evidence.

We conducted a scoping review following the PRISMA-ScR guideline. The protocol was prospectively registered on the Open Science Framework (Registration ID: hn92y). Relevant peer-reviewed English-language studies were searched in PubMed, CINAHL, Cochrane Library, and Web of Science up to January 4, 2025. Reviews, case reports, and conference abstracts were excluded.

Six observational studies (three cross-sectional and three prospective cohorts) met the inclusion criteria after screening 2,814 records. The studies involved both adult and pediatric patients with breast, colorectal, gynecological, and hematologic cancers. Exercise, physical activity, or cardiorespiratory fitness was generally associated with differences in microbial diversity and selected bacterial taxa, including potentially beneficial taxa such as Faecalibacterium, Roseburia, and Akkermansia, and inflammation-related taxa such as Enterococcus. However, wide differences in cancer types, exercise formats, timing, and microbiome analysis methods, together with small sample sizes and limited follow-up, made comparison difficult.

Preliminary evidence suggests that exercise, physical activity, and cardiorespiratory fitness are associated with microbial diversity and selected potentially beneficial bacterial taxa in individuals with cancer. However, the current evidence is limited by observational study designs, small sample sizes, and methodological heterogeneity. Future studies should use standardized exercise protocols, randomized controlled designs, and advanced multi-omics approaches to clarify the functional significance of exercise-related microbiota changes.