International Journal of Radiation Research

en Ileostomy-related dysbiosis after pelvic radiation in colorectal cancer Radiation Biology Radiation Biology تحقيق بديع Original Research <div style="text-align: justify;">Background: Gastrointestinal dysbiosis and inflammation are known complications of pelvic radiation for colorectal cancer, but the effect of diverting ileostomy is not known. This study explored whether ileostomy formation worsens radiotherapy-associated dysbiosis and related clinical complications. Materials and Methods: We performed a prospective matched cohort study of 120 patients with colorectal cancer receiving adjuvant pelvic radiotherapy, including 60 patients with diverting ileostomy and 60 matched non-ileostomy controls. All patients underwent pelvic intensity-modulated radiotherapy with total doses of 45–50.4 Gy in 25–28 fractions. Faecal samples or ileostomy effluent were obtained before radiotherapy, at week 3 and after completion of radiotherapy. Microbial composition was assessed by 16S rRNA sequencing. Alpha diversity, beta diversity, Microbial Dysbiosis Index, bacterial taxa, and clinical outcomes were compared between groups and timepoints. Results: Baseline microbial diversity and dysbiosis scores were similar across groups. Following radiotherapy, the ileostomy group showed a larger reduction in Shannon diversity compared to controls (2.1 ± 0.4 vs. 3.4 ± 0.5, p<0.001) and a higher Microbial Dysbiosis Index (8.2 ± 1.1 vs. 4.5 ± 0.9, p<0.001). Ileostomy patients showed significant depletion of Faecalibacterium prausnitzii and enrichment of Enterococcus faecalis, Clostridium difficile and Escherichia coli. They also had higher rates of dehydration, dermatitis, C. difficile infection and readmission. High dysbiosis post radiotherapy independently predicted readmission. Conclusion: Diverting ileostomy worsens pelvic radiotherapy-induced dysbiosis and is associated with higher treatment-related morbidity in patients with colorectal cancer.</div> Ileostomy, dysbiosis, pelvic radiation, colorectal cancer, microbiome, Clostridium difficile. 1087 1092 http://ijrr.com/browse.php?a_code=A-10-1-1619&slc_lang=en&sid=1 Geriletu 7900319475328460035022 7900319475328460035022 No Department of Gastrointestinal Tumor Surgery, Inner Mongolia Hospital of Peking University Cancer Hospital & The Affiliated Tumor Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia, China E. Li 7900319475328460035023 7900319475328460035023 No Department of Interventional Therapy, Peking University Cancer Hospital, Inner Mongolia Campus & Affiliated Cancer Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia Autonomous Region, China L. Bao 7900319475328460035024 7900319475328460035024 No Department of Endocrinology, Xilingol League Mongolian Medicine Hospital, Inner Mongolia Minzu University, Xilingol League, Inner Mongolia Autonomous Region, China Wurihan 7900319475328460035025 7900319475328460035025 No Department of Gastrointestinal Tumor Surgery, Inner Mongolia Hospital of Peking University Cancer Hospital & The Affiliated Tumor Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia, China X. Wang wudasheng1210@126.com 7900319475328460035026 7900319475328460035026 Yes Department of General Surgery, Xilingol League Mongolian Medicine Hospital, Inner Mongolia Minzu University, Xilingol League, Inner Mongolia Autonomous Region, China Y. Wu 113765055@qq.com 7900319475328460035027 7900319475328460035027 No Department of Gastrointestinal Tumor Surgery, Inner Mongolia Hospital of Peking University Cancer Hospital & The Affiliated Tumor Hospital of Inner Mongolia Medical University, Hohhot, Inner Mongolia, China