Immunonutrition Decreases Postoperative Complications in Gastrointestinal Cancer—A Systematic Review and Meta-analysis of Randomized Controlled Trials

Current evidence supports the role of immunonutrition support (IMNS) to improve surgical outcomes in gastrointestinal (GI) cancer, but the optimal formula and prescription timing remain unclear. This systematic review and meta-analysis aimed to evaluate the efficacy of IMNS on postoperative outcomes in patients with GI cancer. The systematic search was conducted in 3 databases (PubMed, Embase, and Cochrane Library) in March 2024. The protocol was registered at PROSPERO under registration number CRD42024524537. Studies were selected based on the PICOS framework. Population: patients with GI cancer; Intervention: IMNS; Comparator: isonitrogenous and isocaloric supplementation, or standard care; Outcome: mortality, length of hospital stay, and postoperative complications; study design: randomized controlled trial (RCT). Random-effects models were used to calculate pooled odds ratios (OR) or mean differences with 95% confidence intervals (CIs). A total of 90 RCTs were included in the systematic review, with 55 eligible for meta-analysis. Data from 7462 patients were analyzed. IMNS formula based on arginine, nucleotides, and omega-3 (n-3) fatty acids, administered perioperatively, orally or enterally, significantly reduced the odds of anastomotic leak (OR = 0.62; 95% CI: 0.50, 0.76), infectious complications [e.g., respiratory (OR = 0.46; 95% CI: 0.33, 0.64), urinary (OR = 0.58; 95% CI: 0.38, 0.89), wound (OR = 0.67; 95% CI: 0.46, 0.98), and sepsis (OR = 0.45; 95% CI: 0.28, 0.70)], and shortened hospital stay by a mean of 2.47 d (95% CI: -4.13, -0.80). In contrast, ω-3 fatty acids alone did not improve postoperative morbidity. IMNS with arginine, nucleotides, and ω-3 fatty acids improves infection odds and hospital stay without a significant effect on overall survival, whereas ω-3 fatty acids alone did not decrease morbidity odds in patients with GI cancer undergoing surgery.