Enteral immunonutrition versus enteral nutrition for patients undergoing oesophagectomy: a systematic review and meta-analysis.

Objectives: According to retrospective studies, oesophageal carcinoma is the second deadliest gastrointestinal cancer after gastric cancer. Enteral immunonutrition (EIN) has been increasingly used to enhance host immunity and relieve the inflammatory response of patients undergoing oesophagectomy; however, conclusions across studies remain unclear. We aimed to evaluate the effect of EIN on the clinical and immunological outcomes of patients undergoing oesophagectomy.
Methods: Four electronic databases (MEDLINE, Embase, Web of Science and Cochrane Library) were used to search articles in peer-reviewed, English-language journals. The mean difference, relative risk or standard mean difference with 95% confidence interval were calculated. Heterogeneity was assessed by the Cochran's Q test and I2 statistic combined with the corresponding P-value. The analysis was carried out with RevMan 5.3.
Results: Six articles were finally included, with a total of 320 patients with oesophageal cancer. The meta-analysis results showed that EIN did not improve clinical outcomes (such as infectious complications, pneumonia, surgical site infection, anastomotic leak and postoperative hospital stay) or immune indices [referring to C-reactive protein, interleukin (IL)-6, IL-8, tumour necrosis factor-α]. Descriptive analysis suggested that EIN also increased the serum concentrations of IgG and the percentage of the B-cell fraction. Thus, its impact on IL-8 and IL-6 remains inconsistent.
Conclusions: The early-stage impact of EIN on immunological status in patients undergoing oesophagectomy is still unclear. According to the results of this meta-analysis, whether EIN could improve the clinical outcomes or biological status after oesophagectomy compared to standard enteral nutrition is uncertain. Since the impact of EIN is unclear, current guidelines that strongly advise the use of EIN should be changed, as the utility of EIN is very uncertain. More appropriately powered clinical studies are warranted to confirm its effectiveness.
(© The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)