Overview
- The study, which published May 27, 2026, compared stool from 354 women who had adenomas removed with 354 matched adenoma-free women and found lasting differences in gut bacteria and fecal metabolites.
- Researchers used shotgun metagenomic sequencing and identified 31 bacterial species that showed consistent shifts linked to colorectal cancer, including lower Faecalibacterium prausnitzii and higher Flavonifractor plautii.
- The similarity to colorectal cancer microbiomes was modest: investigators estimated about 7% of microbiome differences were explained by adenoma history while 93% reflected individual factors like diet, genetics, and lifestyle.
- Diet quality and physical activity showed stronger associations with cancer-linked microbes in the prior-adenoma group than in controls, pointing to possible routes for modifying risk through behavior or targeted trials.
- Authors stress the findings are observational, apply to a cohort of women from the Nurses' Health Study II, and call for randomized and mechanistic studies to test whether changing diet, exercise, or the microbiome lowers post-adenoma colorectal cancer risk.