Lifestyle-associated gut microbiota signatures in colorectal cancer patients: a pilot case–control study

Background and Objectives Colorectal cancer (CRC) is the third most common cancer in men and the second in women, accounting for 9.4% of cancer-related deaths worldwide in 2020. Increasing evidence highlights the role of gut microbiota in CRC pathogenesis, prognosis, and therapeutic response. Data from Middle Eastern and North African populations remains scarce. This study aimed to analyze gut microbiota profiles in Egyptian patients with CRC and to explore their associations with dietary and lifestyle factors. Material and Methods A pilot case-control study was conducted, involving patients with CRC and healthy controls. Gut microbiota composition was assessed using 16S rRNA gene sequencing, with analysis of microbial diversity and differential taxonomic abundance at the family and genus levels. Dietary patterns, physical activity, and demographic variables were evaluated for their associations with microbial profiles. Results CRC patients exhibited greater microbial heterogeneity, with higher Bray–Curtis distances compared to controls. Several taxa, such as Coprococcus_2 , Ruminococcus , Blautia, and Dorea, were abundant in controls and adjacent normal tissues, whereas Lachnospiraceae UCG-010 was increased in CRC samples. Spicy food intake was linked to enrichment of Prevotellaceae and Christensenellaceae R-7 , while processed meat consumption was associated with reduced abundance of Fusicatenibacter. Regular physical activity was associated with increased Akkermansia abundance among CRC patients. Additionally, sex-specific microbial patterns were observed, with Collinsella , Eggerthella , and Prevotella _ 9 more abundant in males. Conclusions This pilot study identifies clinically relevant, exploratory associations between lifestyle factors and CRC-related microbial signatures in an understudied population. All findings should be considered hypothesis-generating, given the small sample size and cross-sectional design. These results highlight the potential role of modifiable behaviors in microbiome-informed risk stratification. Larger, multi-center studies incorporating multi-omics approaches are warranted to confirm and extend these preliminary observations.