Cancer Rep (Hoboken). 2026 Jun;9(6):e70611. doi: 10.1002/cnr2.70611.
ABSTRACT
BACKGROUND: Post-treatment weight gain and gut dysbiosis are important concerns in breast cancer patients. However, evidence on the gut microbiota in this population, particularly in relation to physical activity, is limited.
AIM: Therefore, we compared gut microbiota in breast cancer patients with obesity with healthy controls and non-cancer controls with obesity and subsequently examined the effects of a combined dance and dietary intervention on gut microbiota, metabolic health, physical fitness, and quality of life.
METHODS AND RESULTS: The observational part compared gut microbiota in breast cancer patients with obesity (BCO, BMI 32.43 ± 4.90 kg/m2) with non-cancer controls with obesity (OC, BMI 37.78 ± 6.68 kg/m2) and healthy controls (HC, BMI 21.26 ± 1.26 kg/m2). A controlled trial was conducted in breast cancer patients with obesity, with an intervention group (INT, n = 13) receiving a 12-week combined dance and dietary intervention and non-intervention controls (CTRL, n = 10). Gut microbiota was assessed using 16S rRNA sequencing, physical fitness was evaluated by an incremental bicycle ergometer test and motor tests, and quality of life was measured using the EORTC QLQ-C30 and BR23 questionnaires. In the observational study, breast cancer patients showed significant differences in beta diversity and a lower relative abundance of health-associated bacteria (e.g., Faecalibacterium prausnitzii) compared with both controls. In the controlled trial, the intervention led to a significant improvement in body composition, physical fitness (e.g., Vo2max, handgrip strength), and several validated quality-of-life domains (e.g., fatigue, body image). A statistically significant difference in beta diversity at the post-intervention phylum level was observed (p = 0.046, R2 = 0.11). Microbiota composition within INT shifted toward, increased health-associated taxa (Bifidobacterium spp.) and reduced opportunistic pathogens (Klebsiella oxytoca). However, a decrease in butyrate-producing taxa (Ruminococcus bromii, Ruminiclostridium hungatei) was also observed.
CONCLUSION: Breast cancer patients showed more negative shifts in gut microbiota compared with both controls. In addition, a 12-week combined dance and dietary intervention improved body composition, physical fitness, quality of life, and was associated with mixed but potentially beneficial changes in select gut microbiota taxa among breast cancer patients with obesity.
TRIAL REGISTRATION: Clinical trial registration number: NCT07213271.
PMID:42321999 | DOI:10.1002/cnr2.70611
