Key Points Question Which approach is best to reduce surgical site infections and anastomotic leak in colorectal surgery: mechanical bowel preparation with oral antibiotics, oral antibiotics only, mechanical bowel preparation only, or no preparation? Findings Among 38 randomized clinical trials (8458 patients) in this network meta-analysis, mechanical bowel preparation with oral antibiotics was associated with the lowest rate of surgical site infections, reducing both incisional and organ/space infections. There was no significant difference in anastomotic leak rate between the 4 approaches. Meaning Mechanical bowel preparation with oral antibiotics is the best approach to reduce surgical site infections in patients undergoing colorectal surgery.

Within an area health service, elective laparoscopic resection for colon and rectal cancer had improved short-term outcomes in comparison with open surgery.

Mesenteric hernias are a rare but important complication of laparoscopic colorectal surgery. The evidence does not support routine closure for all cases, but selective closure of the mesenteric defect during left-sided restorative procedures in high-risk patients at the initial surgery may be considered.

Hypomagnesaemia and associated hypocalcaemia and hypoparathyroidism have been increasingly recognised as rare long-term side-effects of proton pump inhibitors (PPIs). The PPIs may inhibit active magnesium (Mg) absorption by interfering with transcellular transient receptor potential melastatin-6 and -7 (TRPM 6 and 7) channels. More recent cell culture studies have suggested concomitant inhibition of passive Mg absorption by omeprazole. After being treated with a range of PPIs, the four patients in our case series developed hypomagnesaemia, which responded to withdrawal of therapy and initiation of Mg replacement. Their clinical course and management demonstrate key aspects of hypomagnesaemia associated with long-term use of PPIs.

Helicobacter pylori is a class one carcinogen which causes chronic atrophic gastritis, gastric intestinal metaplasia, dysplasia and adenocarcinoma. The mechanisms by which H. pylori interacts with other risk and protective factors, particularly vitamin C in gastric carcinogenesis are complex. Gastric carcinogenesis includes metabolic, environmental, epigenetic, genomic, infective, inflammatory and oncogenic pathways. The molecular classification of gastric cancer subtypes has revolutionized the understanding of gastric carcinogenesis. This includes the tumour microenvironment, germline mutations, and the role of Helicobacter pylori bacteria, Epstein Barr virus and epigenetics in somatic mutations. There is evidence that ascorbic acid, phytochemicals and endogenous antioxidant systems can modify the risk of gastric cancer. Gastric juice ascorbate levels depend on dietary intake of ascorbic acid but can also be decreased by H. pylori infection, H. pylori CagA secretion, tobacco smoking, achlorhydria and chronic atrophic gastritis. Ascorbic acid may be protective against gastric cancer by its antioxidant effect in gastric cytoprotection, regenerating active vitamin E and glutathione, inhibiting endogenous N-nitrosation, reducing toxic effects of ingested nitrosodimethylamines and heterocyclic amines, and preventing H. pylori infection. The effectiveness of such cytoprotection is related to H. pylori strain virulence, particularly CagA expression. The role of vitamin C in epigenetic reprogramming in gastric cancer is still evolving. Other factors in conjunction with vitamin C also play a role in gastric carcinogenesis. Eradication of H. pylori may lead to recovery of vitamin C secretion by gastric epithelium and enable regression of premalignant gastric lesions, thereby interrupting the Correa cascade of gastric carcinogenesis.

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Background: There is a relatively high risk of anastomotic leak in low anterior resection (LAR), associated with significant morbidity and mortality. This systematic review and meta-analysis aims to compare diverting stoma vs. no stoma for LAR in terms of leak rates, reoperations, mortality rates and complication rates. Methods: We systematically performed electronic searches of databases Ovid Medline, PubMed, CCTR, CDSR, ACP Journal Club and DARE from inception to present. Only randomized controlled trials comparing LAR for rectal cancer with versus without stoma diversion were included for analysis. Main outcomes were anastomotic leak, reoperation rate and mortality. Secondary outcomes included other operative and stoma-related complications. Results: Eight randomized controlled trials were included in the study for qualitative and quantitative analyses. A significantly longer operative duration for patients with stoma diversion was seen (WMD 19.50 min; 95% CI: 7.38, 31.63; I 2 =0%, P=0.002). The pooled rate for anastomotic leak was significantly lower for those with stoma diversion (6.3% vs. 18.3%; RR 0.36; 95% CI: 0.24, 0.54; I 2 =0%; P<0.00001). There was lower reoperation rate for patients with stoma diversion compared to no stoma (5.9% vs. 16.7%; RR 0.40; 95% CI: 0.26, 0.60; I 2 =0%; P<0.00001). No significant difference was found in terms of leakrelated mortality between stoma vs. no-stoma cohorts (0.47% vs. 1.0%; P=0.51). Conclusions: The present meta-analysis suggests a diverting or defunctioning stoma following LAR for rectal cancers can reduce anastomotic leak and reoperation rates, without increased risk of mortality or other complications.

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