Objective: To define the influence of preoperative immune modulating nutrition (IMN) on postoperative outcomes in patients undergoing surgery for gastrointestinal cancer. Background: Although studies have shown that perioperative IMN may reduce postoperative infectious complications, many of these have included patients with benign and malignant disease, and the optimal timing of such an intervention is not clear. Methods: The Embase, Medline, and Cochrane databases were searched from 2000 to 2018, for prospective randomized controlled trials evaluating preoperative oral or enteral IMN in patients undergoing surgery for gastrointestinal cancer. The primary endpoint was the development of postoperative infectious complications. Secondary endpoints included postoperative noninfectious complications, length of stay, and up to 30-day mortality. The analysis was performed using RevMan v5.3 software. Results: Sixteen studies reporting on 1387 patients (715 IMN group, 672 control group) were included. Six of the included studies reported on a mixed population of patients undergoing all gastrointestinal cancer surgery. Of the remaining, 4 investigated IMN in colorectal cancer surgery, 2 in pancreatic surgery, and another 2 in patients undergoing surgery for gastric cancer. There was 1 study each on liver and esophageal cancer. The formulation of nutrition used in all studies in the treated patients was Impact (Novartis/Nestlé), which contains ω-3 fatty acids, arginine, and nucleotides. Preoperative IMN in patients undergoing surgery for gastrointestinal cancer reduced infectious complications [odds ratio (OR) 0.52, 95% confidence interval (CI) 0.38–0.71, P < 0.0001, I ² = 16%, n = 1387] and length of hospital stay (weighted mean difference −1.57 days, 95% CI −2.48 to −0.66, P = 0.0007, I ² = 34%, n = 995) when compared with control (isocaloric isonitrogeneous feed or normal diet). It, however, did not affect noninfectious complications (OR 0.98, 95% CI 0.73–1.33, P = 0.91, I ² = 0%, n = 1303) or mortality (OR 0.55, 95% CI 0.18–1.68, P = 0.29, I ² = 0%, n = 955). Conclusion: Given the significant impact on infectious complications and a tendency to shorten length of stay, preoperative IMN should be encouraged in routine practice in patients undergoing surgery for gastrointestinal cancer.

Objective: To define the impact of perioperative treatment with probiotics or synbiotics on postoperative outcome in patients undergoing abdominal surgery. Background: Postoperative surgical infection accounts for a third of all cases of sepsis, and is a leading cause of morbidity and mortality. Probiotics, prebiotics, and synbiotics (preparations that combine probiotics and prebiotics) are nutritional adjuncts that are emerging as novel therapeutic modalities for preventing surgical infections. However, current evidence on their effects is conflicting. Methods: A comprehensive search of the PubMed, Embase, and WHO Global Index Medicus electronic databases was performed to identify randomized controlled trials evaluating probiotics or synbiotics in adult patients undergoing elective colorectal, upper gastrointestinal, transplant, or hepatopancreaticobiliary surgery. Bibliographies of studies were also searched. The primary outcome measure was incidence of postoperative infectious complications. Secondary outcomes included incidence of noninfectious complications, mortality, length of hospital stay, and any treatment-related adverse events. Quantitative pooling of the data was undertaken using a random effects model. Results: A total of 34 randomized controlled trials reporting on 2723 participants were included. In the intervention arm, 1354 patients received prebiotic or symbiotic preparations, whereas 1369 patients in the control arm received placebo or standard care. Perioperative administration of either probiotics or synbiotics significantly reduced the risk of infectious complications following abdominal surgery [relative risk (RR) 0.56; 95% confidence interval (CI) 0.46–0.69; P < 0.00001, n = 2723, I ² = 42%]. Synbiotics showed greater effect on postoperative infections compared with probiotics alone (synbiotics RR: 0.46; 95% CI: 0.33–0.66; P < 0.0001, n = 1399, I ² = 53% probiotics RR: 0.65; 95% CI: 0.53–0.80; P < 0.0001, n = 1324, I ² = 18%). Synbiotics but not probiotics also led to a reduction in total length of stay (synbiotics weighted mean difference: −3.89; 95% CI: −6.60 to −1.18 days; P = 0.005, n = 535, I ² = 91% probiotics RR: −0.65; 95% CI: −2.03–0.72; P = 0.35, n = 294, I ² = 65%). There were no significant differences in mortality (RR: 0.98; 95% CI: 0.54–1.80; P = 0.96, n = 1729, I ² = 0%) or noninfectious complications between the intervention and control groups. The preparations were well tolerated with no significant adverse events reported. Conclusions: Probiotics and synbiotics are safe and effective nutritional adjuncts in reducing postoperative infective complications in elective abdominal surgery. The treatment effects are greatest with synbiotics.

Background Chewing gum as a form of sham feeding is an inexpensive and well-tolerated means of promoting gastrointestinal motility following major abdominal surgery. Although recognised by the Enhanced Recovery After Surgery (ERAS) Society as one of the multimodal approaches to expedite recovery after surgery, strong evidence to support its use in routine postoperative practice is lacking. Methodology A comprehensive literature review of all randomised controlled trials (RCTs) was performed in the Medline and Embase databases between 2000 and 2019. Studies were selected to compare the use of chewing gum versus standard care in the management of postoperative ileus (POI) in adults undergoing colorectal surgery. The primary outcome assessed was the incidence of POI. Secondary outcomes included time to passage of flatus, time to defecation, total length of hospital stay and mortality. Results Sixteen RCTs were included in the systematic review, of which ten (970 patients) were included in the meta-analysis. The incidence of POI was significantly reduced in patients utilising chewing gum compared to those having standard care (RR 0.55, 95% CI 0.39, 0.79, p = 0.0009). These patients also had a significant reduction in time to passage of flatus (WMD − 0.31, 95% CI − 0.36, − 0.26, p < 0.00001) and time to defecation (WMD − 0.47, 95% CI − 0.60, − 0.34, p < 0.00001), without significant differences in the total length of hospital stay or mortality. Conclusion The use of chewing gum after colorectal surgery is a safe and effective intervention in reducing the incidence of POI and merits routine use alongside other ERAS pathways in the postoperative setting.