The Impact of Peri-operative Enteral Immunonutrition on Post-operative Complications in Gastrointestinal Cancer Surgery: A Meta-Analysis

Background: Immunonutrition (IMN) in gastrointestinal (GI) cancer surgery remains under-utilised and contentious. Despite previous meta-analysis reporting benefit, most recent randomised control trials (RCTs) have failed to demonstrate this and have recommended against its routine use. A contemporary meta-analysis may contribute to the recommendations for immunonutrition use and help select which patients may benefit. The objective of this study was to review IMN and its impact on post-operative outcomes in GI cancer surgery, exploring its role in both malnourished and non-malnourished populations, the optimal dose to use, cancer type of patients using IMN and the timing of IMN relative to the peri-operative period.

Patients And Methods: The EMBASE and Medline databases were searched from 2000 to 2022 for RCTs evaluating IMN in adults undergoing GI cancer surgery.

Results: Thirty-seven studies were included (22 pre-operative IMN studies, 11 peri-operative IMN trials and 9 post-operative IMN trials; 4 trials had multiple IMN protocols) that reported on 3793 patients. The main outcome of post-operative infectious complications was reduced with IMN [odds ratio (OR) 0.58, 95% confidence interval (CI) 0.47-0.72]. This association was significant in subgroup analysis only with pre-operative and peri-operative administration and in trials including upper GI cancers, colorectal cancer and 'mixed GI' cancer populations, and significance was independent of nutritional status. IMN in pooled analysis reduced surgical site infection (SSI) (OR 0.65, 95% CI 0.52-0.81), anastomotic leak (OR 0.67, 95% CI 0.47-0.93) and length of stay (LOS) by 1.94 days (95% CI - 3 to - 0.87).

Conclusion: Immunonutrition was associated with reduced post-operative complications. Peri-operative administration may be the preferred strategy in reducing infectious complications, anastomotic leak, SSI and LOS.