Pre-Operative Immunonutrition Enhances Postoperative Outcomes and Elevates Tumor-Infiltrating Lymphocyte Counts in Colorectal Cancer Patients: A Meta-Analysis of Randomized Controlled Trials

Objective: This study (CRD42023464989) aimed to explore the effects of pre-operation immunonutrition on safety and immune related factors in colorectal cancer patients undergoing surgery. Methods: We systematically searched PubMed, Embase, and Wanfang databases to collect all clinical randomized controlled trials of the application of pre-operation immunonutrition for patients with colorectal cancer, published until July 2023. The primary outcomes were safety and immune related factors. Results: A total of 16 studies were finally included. Preoperative immunonutrition could reduce the postoperative infection rate (risk ratio (RR) = 0.56, 95% confidence interval (CI): 0.36, 0.88; p = .01), and wound infection rate (RR = 0.44, 95% CI: 0.27, 0.70; p < .001) in patients with colorectal cancer. For length of stay (mean difference (MD) = -1.10, 95% CI: -2.70, 0.49; p = .17), it was similar between groups. Meanwhile, patients in the pre-operation immune nutrition group also had significantly increased infiltrative lymphocytes CD16+ (MD = 0.04, 95% CI: 0.02, 0.06; p < .001), and CD56+ (MD = 0.05, 95% CI: 0.03, 0.06; p < .001) cells in the tumor tissues, compared to the control group. Conclusion: Immunonutrition intervention has the potential to reduce postoperative infectious complications and improve tumor infiltrative lymphocytes in patients with colorectal cancer undergoing surgery.