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Tiing Leong Ang

Bio: Tiing Leong Ang is an academic researcher from Changi General Hospital. The author has contributed to research in topics: Medicine & Endoscopic ultrasound. The author has an hindex of 38, co-authored 197 publications receiving 4974 citations. Previous affiliations of Tiing Leong Ang include University of Hamburg & The Chinese University of Hong Kong.


Papers
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Journal ArticleDOI
TL;DR: It was recommended that H. pylori infection should be tested for and eradicated prior to long‐term aspirin or non‐steroidal anti‐inflammatory drug therapy in patients at high risk for ulcers and ulcer‐related complications and in communities with high incidence of gastric cancer prevention.
Abstract: The Asia-Pacific Consensus Conference was convened to review and synthesize the most current information on Helicobacter pylori management so as to update the previously published regional guidelines. The group recognized that in addition to long-established indications, such as peptic ulcer disease, early mucosa-associated lymphoid tissue (MALT) type lymphoma and family history of gastric cancer, H. pylori eradication was also indicated for H. pylori infected patients with functional dyspepsia, in those receiving long-term maintenance proton pump inhibitor (PPI) for gastroesophageal reflux disease, and in cases of unexplained iron deficiency anemia or idiopathic thrombocytopenic purpura. In addition, a population 'test and treat' strategy for H. pylori infection in communities with high incidence of gastric cancer was considered to be an effective strategy for gastric cancer prevention. It was recommended that H. pylori infection should be tested for and eradicated prior to long-term aspirin or non-steroidal anti-inflammatory drug therapy in patients at high risk for ulcers and ulcer-related complications. In Asia, the currently recommended first-line therapy for H. pylori infection is PPI-based triple therapy with amoxicillin/metronidazole and clarithromycin for 7 days, while bismuth-based quadruple therapy is an effective alternative. There appears to be an increasing rate of resistance to clarithromycin and metronidazole in parts of Asia, leading to reduced efficacy of PPI-based triple therapy. There are insufficient data to recommend sequential therapy as an alternative first-line therapy in Asia. Salvage therapies that can be used include: (i) standard triple therapy that has not been previously used; (ii) bismuth-based quadruple therapy; (iii) levofloxacin-based triple therapy; and (iv) rifabutin-based triple therapy. Both CYP2C19 genetic polymorphisms and cigarette smoking can influence future H. pylori eradication rates.

547 citations

Journal ArticleDOI
TL;DR: This work critically evaluated strategies for preventing gastric cancer in the Asia–Pacific region and found that conventional and innovative approaches to prevention are likely to be effective.
Abstract: Background and Aim: Gastric cancer is a major health burden in the Asia–Pacific region but consensus on prevention strategies has been lacking. We aimed to critically evaluate strategies for preventing gastric cancer. Methods: A multidisciplinary group developed consensus statements using a Delphi approach. Relevant data were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded. Results: Helicobacter pylori infection is a necessary but not sufficient causal factor for non-cardia gastric adenocarcinoma. A high intake of salt is strongly associated with gastric cancer. Fresh fruits and vegetables are protective but the use of vitamins and other dietary supplements does not prevent gastric cancer. Host–bacterial interaction in H. pylori infection results in different patterns of gastritis and differences in gastric acid secretion which determine disease outcome. A positive family history of gastric cancer is an important risk factor. Low serum pepsinogens reflect gastric atrophy and may be useful as a marker to identify populations at high risk for gastric cancer. H. pylori screening and treatment is a recommended gastric cancer risk reduction strategy in high-risk populations. H. pylori screening and treatment is most effective before atrophic gastritis has developed. It does not exclude the existing practice of gastric cancer surveillance in high-risk populations. In populations at low risk for gastric cancer, H. pylori screening is not recommended. First-line treatment of H. pylori infection should be in accordance with national treatment guidelines. Conclusion: A strategy of H. pylori screening and eradication in high-risk populations will probably reduce gastric cancer incidence, and based on current evidence is recommended by consensus.

317 citations

Journal ArticleDOI
TL;DR: This review summarizes the current epidemiology of H. pylori infection in Asia and analyzes these data in the context of gastric cancer epidemiology.
Abstract: In Asia, the prevalence of Helicobacter pylori (H. pylori) infection varies markedly in different countries. Higher prevalence rates are found in developing Asian countries while lower rates have been reported in more industrialized and developed countries. Within a country, the seroprevalence rates may vary between distinct geographic regions. H. pylori infection is an important etiological factor for the occurrence of non-cardia gastric adenocarcinoma. The incidence rate of gastric adenocarcinoma in Asia tends to mirror the seroprevalence rate of H. pylori infection; however, there are populations with high seroprevalence rates of H. pylori infection that paradoxically have low incidence rates of gastric adenocarcinoma. These diverse clinical outcomes are related to bacterial virulence factors, concomitant environmental factors, host susceptibility and immune response. This review summarizes the current epidemiology of H. pylori infection in Asia and analyzes these data in the context of gastric cancer epidemiology.

290 citations

Journal ArticleDOI
TL;DR: A molecular classification system offers hope for molecularly tailored, personalised therapies for gastric cancer, which may improve the prognosis for patients.
Abstract: Gastric cancer is the second leading cause of cancer-related mortality and the fourth most common cancer globally. There are, however, distinct differences in incidence rates in different geographic regions. While the incidence rate of gastric cancer has been falling, that of gastric cardia cancers is reportedly on the rise in some regions. Helicobacter pylori (H. pylori) infection is a major risk factor of non-cardia gastric cancer, and data has emerged concerning the role of H. pylori eradication for primary prevention of gastric cancer. Dietary, lifestyle and metabolic factors have also been implicated. Although addressing these other factors may contribute to health, the actual impact in terms of cancer prevention is unclear. Once irreversible histological changes have occurred, endoscopic surveillance would be necessary. A molecular classification system offers hope for molecularly tailored, personalised therapies for gastric cancer, which may improve the prognosis for patients.

277 citations

Journal ArticleDOI
TL;DR: Since the publication of the Asia‐Pacific GERD consensus in 2004, more data concerning the epidemiology and management of gastroesophageal reflux disease have emerged and an evidence based review and update was needed.
Abstract: Background and Aims: Since the publication of the Asia-Pacific GERD consensus in 2004, more data concerning the epidemiology and management of gastroesophageal reflux disease (GERD) have emerged. An evidence based review and update was needed. Methods: A multidisciplinary group developed consensus statements using the Delphi approach. Relevant data were presented, and the quality of evidence, strength of recom- mendation, and level of consensus were graded. Results: GERD is increasing in frequency in Asia. Risk factors include older age, male sex, race, family history, higher socioeconomic status, increased body mass index, and smoking. Symptomatic response to a proton pump inhibitor (PPI) test is diagnostic in patients with typical symptoms if alarm symptoms are absent. A negative pH study off therapy excludes GERD if a PPI test fails. The role for narrow band imaging, capsule endoscopy, and wireless pH monitoring has not yet been undefined. Diagnostic strategies in Asia must consider coexistent gastric cancer and peptic ulcer. Weight loss and elevation of head of bed improve reflux symptoms. PPIs are the most effective medical treatment. On-demand therapy is appropriate for nonerosive reflux disease (NERD) patients. Patients with chronic cough, laryngitis, and typical GERD symptoms should be offered twice daily PPI therapy after excluding non-GERD etiologies. Fundoplication could be offered to GERD patients when an experienced surgeon is available. Endoscopic treatment of GERD should not be offered outside clinical trials. Conclusions: Further studies are needed to clarify the role of newer diagnostic modalities and endoscopic therapy. Diagnostic strategies for GERD in Asia must consider coexistent gastric cancer and peptic ulcer. PPIs remain the cornerstone of therapy.

186 citations


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TL;DR: Changing global incidence and mortality patterns for select common cancers and the opportunities for cancer prevention in developing countries are described.
Abstract: While incidence and mortality rates for most cancers (including lung, colorectum, female breast, and prostate) are decreasing in the United States and many other western countries, they are increasing in several less developed and economically transitioning countries because of adoption of unhealthy western lifestyles such as smoking and physical inactivity and consumption of calorie-dense food. Indeed, the rates for lung and colon cancers in a few of these countries have already surpassed those in the United States and other western countries. Most developing countries also continue to be disproportionately affected by cancers related to infectious agents, such as cervix, liver, and stomach cancers. The proportion of new cancer cases diagnosed in less developed countries is projected to increase from about 56% of the world total in 2008 to more than 60% in 2030 because of the increasing trends in cancer rates and expected increases in life expectancy and growth of the population. In this review, we describe these changing global incidence and mortality patterns for select common cancers and the opportunities for cancer prevention in developing countries.

2,577 citations

Journal ArticleDOI
01 Jan 2017-Gut
TL;DR: This fifth edition of the Maastricht Consensus Report describes how experts from 24 countries examined new data related to H. pylori infection in the various clinical scenarios and provided recommendations on the basis of the best available evidence and relevance.
Abstract: Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

2,219 citations

Journal ArticleDOI
01 May 2012-Gut
TL;DR: In this 4th edition of the Maastricht consensus report aspects related to the clinical role of H pylori were looked at again in 2010, with recommendations to guide doctors involved in the management of this infection associated with various clinical conditions.
Abstract: Management of Helicobacter pylori infection is evolving and in this 4th edition of the Maastricht consensus report aspects related to the clinical role of H pylori were looked at again in 2010. In the 4th Maastricht/Florence Consensus Conference 44 experts from 24 countries took active part and examined key clinical aspects in three subdivided workshops: (1) Indications and contraindications for diagnosis and treatment, focusing on dyspepsia, non-steroidal anti-inflammatory drugs or aspirin use, gastro-oesophageal reflux disease and extraintestinal manifestations of the infection. (2) Diagnostic tests and treatment of infection. (3) Prevention of gastric cancer and other complications. The results of the individual workshops were submitted to a final consensus voting to all participants. Recommendations are provided on the basis of the best current evidence and plausibility to guide doctors involved in the management of this infection associated with various clinical conditions.

2,167 citations

Journal ArticleDOI
TL;DR: Large amounts of variation among regions are observed among regions-more than half the world's population is infected, which can be used in development of customized strategies for the global eradication.

1,763 citations