Perioperative immunonutrition in esophageal cancer patients undergoing esophagectomy: the first meta-analysis of randomized clinical trials

Although several randomized controlled trials have been published in recent years, the effect of perioperative immunonutrition in esophageal cancer (EC) patients remains unclear. This initial meta-analysis was conducted to assess whether perioperative enteral immunonutrition reduces postoperative complications in patients undergoing esophagectomy for EC. Relevant randomized controlled trials published before 1st September 2019 were retrieved from the Cochrane Library, PubMed, and EMBASE databases. After the literature was screened, two researchers extracted the information and data from eligible studies according to predefined selection criteria. Obtained data were pooled and analyzed by RevMan 5.3 software. The results were presented as risk ratios (RRs) with 95% confidence intervals (CIs). The heterogeneity among studies was tested by I-2 test. Seven high-quality randomized controlled trials were included, with a total of 606 patients, 311 of whom received immunonutrition before and after surgery, while 295 received perioperative standard nutrition. No significant difference was observed between the two groups in the incidence of postoperative infection complications, including total infection complications (RR = 0.97, CI: 0.78-1.20, P = 0.76), pneumonia (RR = 0.97, CI: 0.71-1.33, P = 0.84), wound infection (RR = 0.80, CI: 0.46-1.40, P = 0.44), sepsis (RR = 1.35, CI: 0.67-2.71, P = 0.40), and urinary tract infection (RR = 0.87, CI: 0.54-1.40, P = 0.56). The prevalence of anastomotic leakage in the two groups was 9.4 and 5.4%, but the difference was not statistically significant (RR = 0.59, CI: 0.33-1.04, P = 0.07). Perioperative enteral immunonutrition provided no benefit in terms of the incidence of infection complications and anastomotic leakage in EC patients undergoing esophagectomy. Further large-scale randomized controlled trials are needed to confirm this conclusion.