Effect of preoperative immunonutrition on outcomes of colon cancer surgery: study protocol for a randomized controlled trial

BACKGROUND: Current guidelines recommend the prescription of immune-enriched oral nutritional supplements for malnourished patients before major gastrointestinal surgery. However, the benefit of preoperative immunonutrition is still controversial. This randomized controlled trial aims to evaluate the effect of preoperative immunonutrition on the outcomes of surgery for colon cancer. METHODS/DESIGN: Patients with primary colon cancer will be included as study participants after screening. They will be randomly assigned (in a ratio of 1:1) to receive preoperative immunonutrition added to the normal diet (experimental arm) or consume normal diet alone (control arm). Patients in the experimental arm will receive oral supplementation (400 mL/day) with arginine and ω-3 fatty acids for 7 days before elective surgery. The primary endpoint is the rate of infectious complications, while the secondary endpoints are postoperative complication rate, change in body weight, length of hospital stay, and nature of fecal microbiome. The authors hypothesize that the rate of infectious complications would be 13% in the experimental arm and 30% in the control arm. With a two-sided alpha of 0.05 and a power of 0.8, the sample size is calculated as 176 patients (88 per arm). DISCUSSION: Although there have been many studies demonstrating significant benefits of preoperative immunonutrition, these were limited by a small sample size and potential publication bias. Despite the recommendation of immunonutrition before surgery in nutritional guidelines, its role in reduction of rate of infectious complications is still controversial. This trial is expected to provide evidence for the benefits of administration of preoperative immunonutrition in patients with colon cancer. TRIAL REGISTRATION: Clinical Research Information Service KCT0003770. Registered on 15 April 2019.