Presentation Information
[SY7-5]Correlation between changes in intestinal microbiota and defecatory function before and after radical resection of right-sided colon cancer.
*Sohei Akuta1,2, Masataka Hirasaki3, Yume Minagawa1, Akihito Nakanishi1, Yusuke Nishi1, Hisashi Hayashi1, Takatsugu Fujii1, Yasuhiro Ishiyama1, Hirofumi Sugita1, Chikashi Hiranuma1, Yasumitsu Hirano1 (1. Department of Gastrointestinal Surgery, Saitama Medical University International Medical Center, Japan, 2. Department of Gastrointestinal Surgery, Tsuchiura Kyodo General Hospital, Japan, 3. Department of Cancer Genomics Center, Saitama Medical University International Medical Center)
Postoperative bowel dysfunction after colorectal cancer surgery impairs quality of life; however, its longitudinal course and association with gut microbiota dynamics after right-sided colon cancer surgery remain unclear. This single-center retrospective observational study included 60 patients with pathological stage I–III right-sided colon cancer who underwent curative ileocecal resection or right hemicolectomy 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 composition was evaluated using full-length 16S rRNA sequencing of fecal samples collected preoperatively and at 1 and 6 months postoperatively. Bowel function parameters showing significant postoperative changes were identified, and patients were stratified according to the presence or absence of symptom worsening to assess the effects of sampling time, symptom-based phenotype group, and their interaction on microbial diversity.
At 1 month postoperatively, stool softening, incomplete evacuation, and liquid stool incontinence were observed in 42, 21, and 5 patients, respectively. These symptoms improved by 6 months and generally returned to preoperative levels by 12 months. Microbiota analysis revealed decreased α-diversity and marked early shifts in β-diversity, followed by gradual reconstruction with substantial interindividual variability. In phenotype-stratified analyses, microbial diversity changes were consistently associated with sampling time, whereas symptom-based group effects and time × group interactions were not significant. Overall, bowel dysfunction after right-sided colon cancer surgery was common but largely transient, and postoperative microbiota alterations appeared to reflect generalized, time-dependent ecological reconstruction rather than direct microbial correlates of individual bowel symptoms.
At 1 month postoperatively, stool softening, incomplete evacuation, and liquid stool incontinence were observed in 42, 21, and 5 patients, respectively. These symptoms improved by 6 months and generally returned to preoperative levels by 12 months. Microbiota analysis revealed decreased α-diversity and marked early shifts in β-diversity, followed by gradual reconstruction with substantial interindividual variability. In phenotype-stratified analyses, microbial diversity changes were consistently associated with sampling time, whereas symptom-based group effects and time × group interactions were not significant. Overall, bowel dysfunction after right-sided colon cancer surgery was common but largely transient, and postoperative microbiota alterations appeared to reflect generalized, time-dependent ecological reconstruction rather than direct microbial correlates of individual bowel symptoms.