Immunonutrition Versus Standard Nutrition for Cancer Patients: A Systematic Review and Meta-Analysis

Background: Whether cancer patients receive benefits from immunonutrition is unclear. We systematically reviewed the effect of immunonutrition versus standard nutrition on cancer patients. Methods: The Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, MEDLINE, EBSCOhost, and Web of Science were searched for studies reporting clinical outcomes comparing immunonutrition with standard nutrition from the date of database inception to May 28, 2018. We assessed the risk of bias using the Cochrane risk of bias tool and the quality of evidence using the grading of recommendations assessment, development, and evaluation approach. Findings: In total, 79 randomized controlled trials with a total of 6970 adult cancer patients were included in the final pooled analysis. Compared with standard nutrition, immunonutrition was associated with a significantly lower risk of postoperative infection complications (RR 0*71 [95% CI 0*64 - 0*79], p<0*00001, I²=0), including a lower risk of wound infection (RR 0*72 [95% CI 0*60 - 0*87], p=0*0007, I²=0), respiratory tract infection (RR 0*70 [95% CI 0*59 - 0*84], p=0*0001, I²=0), and urinary tract infection (RR 0*69 [95% CI 0*51 - 0*964, p=0*02, I²=0), as well as a lower risk of anastomotic leakage (RR 0*70 [95% CI 0*53 - 0*91], p=0*009, I²=0) and a shorter hospital stay (RR -2*12 days [95% CI -2*72 to -1*52], p<0*00001, I2=82%). Among cancer patients who underwent surgery, no differences were found between the two groups with regard to sepsis (RR 0*75 [95% CI 0*45 - 1*25], p=0*27, I²=0) or all-cause mortality (RR 1*00 [95% CI 0*69-1*43], p=0*99, I²=0). Among chemoradiotherapy patients, no differences were found between the two groups with regard to oral mucositis (RR 0*95, 95% CI 0*86 to 1*04, I²=0), diarrhea (RR 0*96, 95% CI 0*81 to 1*13, I²=0) or all-cause mortality (RR 0*43, 95% CI 0*10 to 1*82, I²=0). Interpretation: This systematic review and meta-analysis provides evidence that for surgical cancer patients, immunonutrition reduces postoperative infection complications (moderate quality) and shortens hospital stays (low quality) but does not reduce all-cause mortality (moderate quality); for chemoradiotherapy patients, immunonutrition is not superior to standard nutrition in improving oral mucositis (very low quality), diarrhea (low quality) or all-cause mortality (low quality). Funding Statement: This work was supported by the National Natural Science Foundation of China (No. 81571871 and 81770276); Nn10 program and Distinguished Young Scholars Fund of Harbin Medical University Cancer Hospital; the Yuweihan Fund for Distinguished Young Scholars of Harbin Medical University; Harbin Science and Technology Innovation Scholars Fund (2017RAXXJ087); Heilongjiang Province Postdoctoral Research Fund Declaration of Interests: All authors have completed the ICMJE uniform disclosure form at icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work; no other relationships or activities that could appear to have influenced the submitted work. Ethics Approval Statement: The authors declare Ethical Approval: "Not required."