Effect of immunonutrition on colorectal cancer patients undergoing surgery: a meta-analysis

Immunonutrition has been used to prevent the complications after colorectal elective surgery. This systematic review aimed to analyze and assess the effect of immunonutrition on colorectal cancer patients who received elective surgery. Three electronic databases (Medline, Embase, Cochrane) were used to search the latent studies which investigated the effects of enteral immunonutrition (EIN) compared with standard enteral nutrition (EN) or parenteral immunonutrition (PIN) compared with standard parenteral nutrition (PN) on colorectal cancer patients who are undergoing surgery until 21st of April, 2017. Meta-analysis was conducted to calculate odd risk (OR), mean difference (MD), or standard mean difference (SMD) with 95% confidence interval (CI), and heterogeneity was tested by Q test. Nine publications were included. The meta-analysis results presented that EIN improved the length of hospital stay (pooled MD, 2.53; 95% CI, 1.29-3.41), infectious complications (pooled OR, 0.33; 95% CI, 0.21-0.53) which contains the Surgical Site Infections (pooled OR, 0.25; 95% CI, 0.22-0.58) and Superficial/Deep incisional infections (pooled OR, 0.27; 95% CI, 0.12-0.64); meanwhile, PIN improved the length of hospital stay (pooled MD, 2.66; 95% CI, 0.62-4.76), IL-6 (pooled MD, - 6.09; 95% CI, - 10.11 to - 2.07), CD3 (pooled MD, 7.50; 95% CI, 3.57-11.43), CD4 (pooled MD, 5.47; 95% CI, 2.54-8.40), and CD4/CD8 (pooled MD, 0.50; 95% CI, 0.22-0.78); the level of CD8 was lower (pooled MD, - 4.32; 95% CI, - 7.09 to - 1.55) in PIN. Immunonutrition could be an effective approach to enhance the immune function of colorectal cancer patients undergoing elective surgery and to improve the clinical and laboratory outcomes.