LAUSR

Introduction Gut microbiota (GM) appears critical for gastrointestinal symptoms, but whether alterations in GM are associated with increased risk of postoperative gastrointestinal dysfunction (POGID) in older patients with colon cancer (CC) undergoing elective colon resection remains unclear. Methods and analysis This study aims to prospectively recruit 284 elderly patients with CC undergoing elective colon resection. GM of fresh faeces specimens is characterised using 16S rRNA gene sequencing. Data are collected preoperatively, daily postoperatively during the in-hospital stay, and follow-up visits are scheduled four times within 30 days after discharge. Associations with POGID will be investigated using logistic regression models to calculate ORs with 95% CIs. The models include the adjustment for age, sex, frequency of spicy diet, coffee drinking and tea drinking, tobacco and alcohol history, diabetes, obesity, gastroenteritis, preoperative gut microbial composition. Furthermore, we will use joint modelling for longitudinal data to study several outcome variables simultaneously. Ethics and dissemination This study was approved by the Institutional Review Board of West China Hospital, Sichuan University (IRB Number: 20201334). The results will be disseminated through peer-reviewed publications or conference presentations. Trial registration number It has been registered in PROSPERO, number CRD42019145032. It has been registered in the Chinese clinical trial registry, number ChiCTR2100043646.