Risk of gastric cancer development after eradication of Helicobacter pylori

Helicobacter pylori(H. pylori) infection is the most important risk factor for gastric cancer(gc) development through the correa's gastric carcinogenesis cascade. However, H. pylori eradication alone does not eliminate gc, as pre-neoplastic lesions(atrophic gastritis, intestinal metaplasia and dysplasia) may have already developed in some patients. It is therefore necessary to identify patients at high-risk for gastric cancer after H. pylori eradication to streamline the management plan. If the patients have not undergone endoscopy with histologic assessment, the identification of certain clinical risk factors and non-invasive testing(serum pepsinogen) can predict the risk of atrophic gastritis. For those with suspected atrophic gastritis, further risk stratification by endoscopy with histologic assessment according to validated histologic staging systems would be advisable. Patients with higher stages may require long-term endoscopic surveillance. Apart from secondary prevention to reduce deaths by diagnosing gc at an early stage, identifying medications that could potentially modify the gc risk would be desirable. The potential roles of a number of medications have been suggested by various studies, including proton pump inhibitors(PPIs), aspirin, statins and metformin. However, there are currently no randomized clinical trials to address the impact of these medications on gc risk after H. pylori eradication. In addition, most of these studies failed to adjust for the effect of concurrent medications on gc risk. Recently, large population-based retrospective cohort studies have shown that PPIs were associated with an increased gc risk after H. pylori eradication, while aspirin was associated with a lower risk. The roles of other agents in reducing gc risk after H. pylori eradication remain to be determined.

Gastrointestinal bleeding in patients on novel oral anticoagulants:Risk,prevention and management

Novel oral anticoagulants(NOACs), which include direct thrombin inhibitor(dabigatran) and direct factor Xa inhibitors(rivaroxaban, apixaban and edoxaban), are gaining popularity in the prevention of embolic stroke in non-valvular atrial fibrillation as well as in the prevention and treatment of venous thromboembolism. However, similar to traditional anticoagulants, NOACs have the side effects of bleeding, including gastrointestinal bleeding(GIB). Results from both randomized clinical trials and observations studies suggest that high-dose dabigatran(150 mg b.i.d), rivaroxaban and high-dose edoxaban(60 mg daily) are associated with a higher risk of GIB compared with warfarin. Other risk factors of NOAC-related GIB include concomitant use of ulcerogenic agents, older age, renal impairment, Helicobacter pylori infection and a past history of GIB. Prevention of NOAC-related GIB includes proper patient selection, using a lower dose of certain NOACs and in patients with renal impairment, correction of modifiable risk factors, and prescription of gastroprotective agents. Overt GIB can be managed by withholding NOACs followed by delayed endoscopic treatment. In severe bleeding, additional measures include administration of activated charcoal, use of specific reversal agents such as idarucizumab for dabigatran and andexanent alfa for factor Xa inhibitors, and urgent endoscopic management.

Helicobacter pylori associated gastric intestinal metaplasia:Treatment and surveillance

Gastric cancer(GC) is one of the leading causes of cancer related death in the world, particularly in East Asia. According to the Correa's cancer cascade, noncardia GC is usually developed through a series of mucosal changes from non-atrophic gastritis to atrophic gastritis(AG), intestinal metaplasia(IM), dysplasia and adenocarcinoma. Atrophic gastritis and IM are therefore generally considered to be pre-neoplastic gastric lesions. Helicobacter pylori(H. pylori) infection is an important initiating and promoting step of this gastric carcinogenesis cascade. Emerging long-term data showed that eradication of H. pylori reduced the risk of subsequent cancer development. It however remains confusing whether eradication of the bacterium in individuals with pre-neoplastic gastric lesions could regress these changes as well as in preventing cancer. Whilst H. pylori eradication could likely regress AG, the presence of IM may be a point of no return in this cascade. Hence, surveillance by endoscopy may be indicated in those with extensive IM or those with incomplete IM, particularly in populations with high GC risk. The optimal interval and the best tool of surveillance endoscopy remains to be determined in future studies.

Effect of oral erythromycin on gastric and small bowel transit time of capsule endoscopy

AIM: To determine the effect of oral erythromycin on gastric and small bowel transit time of capsule endoscopy.METHODS: Consecutive patients who underwent capsule endoscopy du ring the 16-mo study period were either given 250 mg oral erythromycin, 1 h prior to swallowing the capsule endoscope or nothing. The gastric and small bowel transit time, and the small bowel image quality were compared.RESULTS: Twenty-four patients received oral erythromycin whereas 14 patients were not given any prokinetic agent.Patients who received erythromycin had a significantly lower gastric transit time than control (16 min vs70 min, P= 0.005),whereas the small bowel transit time was comparable between the two groups (227 min vs183 min, P = 0.18).Incomplete small bowel examination was found in three patients of the control group and in one patient of the erythromycin group. There was no significant difference in the overall quality of small bowel images between the two groups. A marked reduction in gastric transit time was noted in two patients who had repeat capsule endoscopy after oral erythromycin.CONCLUSION: Use of oral erythromycin significantly reduces the gastric transit time of capsule endoscopy.

Is artificial intelligence the final answer to missed polyps in colonoscopy?

Lesions missed by colonoscopy are one of the main reasons for post-colonoscopy colorectal cancer,which is usually associated with a worse prognosis.Because the adenoma miss rate could be as high as 26%,it has been noted that endoscopists with higher adenoma detection rates are usually associated with lower adenoma miss rates.Artificial intelligence(AI),particularly the deep learning model,is a promising innovation in colonoscopy.Recent studies have shown that AI is not only accurate in colorectal polyp detection but can also reduce the miss rate.Nevertheless,the application of AI in real-time detection has been hindered by heterogeneity of the AI models and study design as well as a lack of long-term outcomes.Herein,we discussed the principle of various AI models and systematically reviewed the current data on the use of AI on colorectal polyp detection and miss rates.The limitations and future prospects of AI on colorectal polyp detection are also discussed.

Application of Big Data analysis in gastrointestinal research

Big Data,which are characterized by certain unique traits like volume,velocity and value,have revolutionized the research of multiple fields including medicine.Big Data in health care are defined as large datasets that are collected routinely or automatically,and stored electronically.With the rapidly expanding volume of health data collection,it is envisioned that the Big Data approach can improve not only individual health,but also the performance of health care systems.The application of Big Data analysis in the field of gastroenterology and hepatology research has also opened new research approaches.While it retains most of the advantages and avoids some of the disadvantages of traditional observational studies(case-control and prospective cohort studies),it allows for phenomapping of disease heterogeneity,enhancement of drug safety,as well as development of precision medicine,prediction models and personalized treatment.Unlike randomized controlled trials,it reflects the real-world situation and studies patients who are often under-represented in randomized controlled trials.However,residual and/or unmeasured confounding remains a major concern,which requires meticulous study design and various statistical adjustment methods.Other potential drawbacks include data validity,missing data,incomplete data capture due to the unavailability of diagnosis codes for certain clinical situations,and individual privacy.With continuous technological advances,some of the current limitations with Big Data may be further minimized.This review will illustrate the use of Big Data research on gastrointestinal and liver diseases using recently published examples.