Correlation between changes in intestinal microbiota and defecatory function before and after radical resection of right-sided colon cancer

Postoperative bowel dysfunction after colorectal cancer surgery impairs quality of life, but its longitudinal course and relationship with the gut microbiota after right-sided colon cancer surgery remain unclear. We retrospectively analyzed 60 patients who underwent curative resection for right-sided colon cancer between November 2023 and November 2024. Bowel function was assessed preoperatively and at 1, 6, and 12 months postoperatively using the Bristol Stool Form Scale, Constipation Scoring System, and Wexner score. Gut microbiota was analyzed by full-length 16S rRNA sequencing of fecal samples collected preoperatively and at 1 and 6 months after surgery. At 1 month, stool softening, incomplete evacuation, and incontinence to liquid stool were observed in 42, 21, and 5 patients, respectively. These symptoms improved after 6 months and generally returned to preoperative levels by 12 months. Microbiota analysis showed decreased α-diversity and marked shifts in β-diversity during the early postoperative period, followed by gradual reconstruction with interindividual variability. Collectively, bowel dysfunction after right-sided colon cancer surgery was common but largely transient, whereas gut microbiota changes were predominantly time-dependent rather than symptom-specific, suggesting generalized ecological reconstruction rather than direct microbial correlates of individual bowel symptoms.