Immunonutrition for patients undergoing surgery for head and neck cancer.

Background: Patients with head and neck cancer are often malnourished. Surgery for such cancers is complex and may be undertaken after a course of radiotherapy. As a result, patients may have postoperative complications such as fistulae and wound infections, as well as more generalised infections such as pneumonia. One possible way to enhance recovery, and reduce the incidence of these complications, is by improving nutrition. Nutritional formulas that deliver basic nutrients as well as amino acids (arginine and glutamine), ribonucleic acid (RNA) and/or lipids (omega-3 fatty acids) are known as immunonutrition.

Objectives: To assess the effects of immunonutrition treatment, compared to standard feeding, on postoperative recovery in adult patients undergoing elective (non-emergency) surgery for head and neck cancer.

Search Methods: The Cochrane ENT Information Specialist searched the ENT Trials Register; Central Register of Controlled Trials (CENTRAL); PubMed; Ovid Embase; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 February 2018.

Selection Criteria: We included randomised controlled trials (RCTs) comparing immunonutrition given either preoperatively, postoperatively or perioperatively to adult patients (18 years of age or older) undergoing an elective surgical procedure for head and neck cancer, compared with a control group receiving either standard polymeric nutritional supplements or no supplements.

Data Collection And Analysis: We used the standard methodological procedures expected by Cochrane. The primary outcomes were: length of hospital stay (days), wound infection, fistula formation and adverse events/tolerance of feeds, as defined by trial authors. Secondary outcomes were: all-cause mortality and postoperative complications (as defined by trial authors). We used GRADE to assess the quality of the evidence for each outcome; this is indicated in italics.

Main Results: We included 19 RCTs (1099 participants). The mean age of participants ranged from 47 to 66 years. Most studies (12/19) had fewer than 25 patients in each treatment group. Most studies (16/19) used immunonutrition formulas containing arginine, but there was variation in the actual products and amounts used, and in the length of intervention postoperatively. Follow-up time for outcome measurement varied considerably across studies, ranging from five days to greater than or equal to 16 months.Primary outcomesWe found no evidence of a difference in the length of hospital stay (mean difference -2.5 days, 95% confidence interval (CI) -5.11 to 0.12; 10 studies, 757 participants; low-quality evidence). Similarly, we found no evidence of an effect of immunonutrition on wound infection (risk ratio (RR) 0.94, 95% CI 0.70 to 1.26; 12 studies, 812 participants; very low-quality evidence). Fistula formation may be reduced with immunonutrition; the absolute risks were 11.3% and 5.4% in the standard care and immunonutrition groups, with a RR of 0.48 (95% CI 0.27 to 0.85; 10 studies, 747 participants; low-quality evidence). We found no evidence of a difference in terms of tolerance of feeds ('adverse events') between treatments (RR 1.33, 95% CI 0.86 to 2.06; 9 studies, 719 participants; very low-quality evidence).Secondary outcomesWe found no evidence of a difference between treatments in all-cause mortality (RR 1.33, 95% CI 0.48 to 3.66; 14 studies, 776 participants; low-quality evidence). Other postoperative complications such as pneumonia and urinary tract infections were not commonly reported.

Authors' Conclusions: The risk of postoperative fistula formation may be reduced with immunonutrition, but we found no evidence of an effect of immunonutrition on any of the other outcomes that we assessed. The studies included in this review were generally small or at high risk of bias (or both). We judged the overall quality of the evidence to be low for the outcomes length of hospital stay and all-cause mortality, and very low for wound infection and adverse events. Further research should include larger, better quality studies.