Chemopreventive Effect of Metformin on Gastric Cancer Development

Although Helicobacter pylori infection is the most important causative factor for gastric cancer (GC), H. pylori eradication alone does not completely eliminate the GC risk. In addition to H. pylori eradication, other risk factors for GC should be identified and targeted. Diabetes mellitus (DM) confers a 20% increased risk of GC, which could be mediated via several biological mechanisms including the stimulation of cell proliferation via hyperinsulinemia and increased insulingrowth factor production, the promotion of angiogenesis, and DNA damage. With a current global prevalence of 9.3% and a predicted rise to 10.2% by 2030, DM could contribute substantially to the burden of GC cases worldwide. Emerging evidence showed that metformin possesses chemopreventive effects via both direct (e.g., adenosine monophosphate-activated protein kinase activation and subsequent inhibition of the mammalian target of rapamycin pathway) and indirect (e.g., modulation of the interaction between tumor cells and their microenvironment and gut microbiota) pathways. A recent meta-analysis of observational studies showed that metformin use was associated with 24% lower GC risk. However, many available observational studies related to metformin effects suffered from biases including the failure to adjust for theH. pylori infection status and serial glycemic control and time-related biases. Future prospective studies addressing these pitfalls are needed.

Potential Strategies in the Prevention of Nonsteroidal Anti-inflammatory Drugs-Associated Adverse Effects in the Lower Gastrointestinal Tract

With the increasing use of nonsteroidal anti-inflammatory drugs (NSAIDs), the incidence of lower gastrointestinal (GI) complications is expected to increase. However, unlike upper GI complications, the burden, pathogenesis, prevention and treatment of NSAID-associated lower GI complications remain unclear. To date, no cost-effective and safe protective agent has been developed that can completely prevent or treat NSAID-related lower GI injuries. Selective COX-2 inhibitors, misoprostol, intestinal microbiota modulation, and some mucoprotective agents have been reported to show protective effects on NSAID-induced lower GI injuries. This review aims to provide an overview of the current evidence on the prevention of NSAID-related lower GI injuries.

Rates of metachronous adenoma after curative resection for left-sided or right-sided colon cancer

BACKGROUND/AIMS: We determined the rates of metachronous colorectal neoplasm in colorectal cancer (CRC) patients after resection for right (R)-sided or left (L)-sided cancer. METHODS: Consecutive CRC patients who had undergone surgical resection for curative intent in our hospital between 2001 and 2004 were identified. R-sided colonic cancers refer to cancer proximal to splenic flexure whereas L-sided cancers include rectal cancers. Patients were included only if they had a clearing colonoscopy performed either before or within 6 months after the operation. Findings of surveillance colonoscopy performed up to 5 years after colonic resection were included in the analysis. RESULTS: Eight hundred and sixty-three CRC patients underwent curative surgical resection during the study period. Three hundred and twenty-seven patients (107 R-sided and 220 L-sided) fulfilled the inclusion criteria and had at least 1 postoperative surveillance colonoscopy performed. The proportion of patients who had polyp and adenoma on surveillance colonoscopy was significantly higher among patients with L-sided than R-sided cancers (polyps: 30.9% vs. 19.6%, P=0.03; adenomas: 25.5% vs. 13.1%, P=0.01). The mean number of adenoma per patient on surveillance colonoscopy was also higher for patients with L-sided than R-sided tumors (0.52; 95% confidence interval [CI], 0.37–0.68 vs. 0.22; 95% CI, 0.08–0.35; P < 0.01). Multivariate analysis showed that L-sided cancers, age, male gender and longer follow-up were independent predictors of adenoma detection on surveillance colonoscopy. CONCLUSIONS: Patients with Lsided cancer had a higher rate of metachronous polyps and adenoma than those with R-sided cancer on surveillance colonoscopy.

Optimization of Inflammatory Bowel Disease Cohort Studies in Asia

With the incidence of inflammatory bowel disease (IBD) increasing rapidly in many Asian countries, including Hong Kong, it is important that patient characteristics are better understood. For example, are the phenotypes, behaviors, complications, and even treatment responses found in Asian patients similar to those of their Western counterparts? To formally address these questions, a properly designed local cohort study is needed. Whilst IBD is still relatively uncommon in Asia, the establishment of a local IBD registry will significantly contribute to the answering of these questions. The Hong Kong IBD registry was established to fill the gap in the understanding of IBD patients, and to foster research into IBD in Hong Kong. The Hong Kong IBD registry is a territory-wide registry that includes all public hospitals in Hong Kong. We included all IBD patients who were currently receiving medical care at these hospitals. With the help of the central computer medical record system of the Hospital Authority of Hong Kong, all clinical events, medications usage, endoscopy records, and laboratory results of patients in the registry were captured. Apart from data collection, the registry is also establishing a bio-specimen bank of blood and stool samples of IBD patients for future research. The IBD registry is a very useful platform for population-based studies on IBD in Asia.