Khean-Lee Goh

Increasing incidence of colorectal cancer in Asia: implications for screening

Many Asian countries, including China, Japan, South Korea, and Singapore, have experienced an increase of two to four times in the incidence of colorectal cancer during the past few decades. The rising trend in incidence and mortality from colorectal cancer is more striking in affluent than in poorer societies and differs substantially among ethnic groups. Although changes in dietary habits and lifestyle are believed to be the reasons underlying the increase, the interaction between these factors and genetic characteristics of the Asian populations might also have a pivotal role. Non-polypoidal (flat or depressed) lesions and colorectal neoplasms arising without preceding adenoma (de novo cancers) seem to be more common in Asian than in other populations. The absence of polypoid growth preceding malignancy has posed difficulties in screening for early colorectal cancer by radiological imaging or even endoscopic techniques. Although epidemiological data are scanty, most Asian populations are not aware of the growing problem of colorectal cancer. More work is needed to elucidate the magnitude of the problem in Asia.

Screening for gastric cancer in Asia: current evidence and practice

Gastric cancer is the second most common cause of death from cancer in Asia. Although surgery is the standard treatment for this disease, early detection and treatment is the only way to reduce mortality. This Review summarises the epidemiology of gastric cancer, and the evidence for, and current practices of, screening in Asia. Few Asian countries have implemented a national screening programme for gastric cancer; most have adopted opportunistic screening of high-risk individuals only. Although screening by endoscopy seems to be the most accurate method for detection of gastric cancer, the availability of endoscopic instruments and expertise for mass screening remains questionable--even in developed countries such as Japan. Therefore, barium studies or serum-pepsinogen testing are sometimes used as the initial screening tool in some countries, and patients with abnormal results are screened by endoscopy. Despite the strong link between infection with Helicobacter pylori and gastric cancer, more data are needed to define the role of its eradication in the prevention of gastric cancer in Asia. At present, there is a paucity of quality data from Asia to lend support for screening for gastric cancer.

Second Asia–Pacific Consensus Guidelines for Helicobacter pylori infection

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.

Asia Pacific consensus recommendations for colorectal cancer screening

Colorectal cancer (CRC) is rapidly increasing in Asia, but screening guidelines are lacking. Through reviewing the literature and regional data, and using the modified Delphi process, the Asia Pacific Working Group on Colorectal Cancer and international experts launch consensus recommendations aiming to improve the awareness of healthcare providers of the changing epidemiology and screening tests available. The incidence, anatomical distribution and mortality of CRC among Asian populations are not different compared with Western countries. There is a trend of proximal migration of colonic polyps. Flat or depressed lesions are not uncommon. Screening for CRC should be started at the age of 50 years. Male gender, smoking, obesity and family history are risk factors for colorectal neoplasia. Faecal occult blood test (FOBT, guaiac-based and immunochemical tests), flexible sigmoidoscopy and colonoscopy are recommended for CRC screening. Double-contrast barium enema and CT colonography are not preferred. In resource-limited countries, FOBT is the first choice for CRC screening. Polyps 5–9 mm in diameter should be removed endoscopically and, following a negative colonoscopy, a repeat examination should be performed in 10 years. Screening for CRC should be a national health priority in most Asian countries. Studies on barriers to CRC screening, education for the public and engagement of primary care physicians should be undertaken. There is no consensus on whether nurses should be trained to perform endoscopic procedures for screening of colorectal neoplasia.

World Gastroenterology Organization Practice Guidelines for the Diagnosis and Management of IBD in 2010

Inflammatory bowel disease (IBD) represents a group of idiopathic, chronic, inflammatory intestinal conditions. Its two main disease categories are: Crohns disease (CD) and ulcerative colitis (UC), which feature both overlapping and distinct clinical and pathological features. While these diseases have, in the past, been most evident in the developed world, their prevalence in the developing world has been gradually increasing in recent decades. This poses unique issues in diagnosis and management which have been scarcely addressed in the literature or in extant guidelines. Depending on the nature of the complaints, investigations to diagnose either form of IBD or to assess disease activity will vary and will also be influenced by geographic variations in other conditions that might mimic IBD. Similarly, therapy varies depending on the phenotype of the disease being treated and available resources. The World Gastroenterology Organization has, accordingly, developed guidelines for diagnosing and treating IBD using a cascade approach to account for variability in resources in countries around the world.

How common is non‐alcoholic fatty liver disease in the Asia–Pacific region and are there local differences?

Risk factors for development of non‐alcoholic steatohepatitis include obesity, especially central adiposity, glucose intolerance or type 2 diabetes mellitus (T2DM), and dyslipidemia. Non‐alcoholic fatty liver disease (NAFLD) is now considered a manifestation of metabolic syndrome. During the last two decades, NAFLD has become the most common chronic liver disease in North America and Europe, but until recently was thought to be uncommon (perhaps due to the lack of study) in Asia. Fatty liver can be identified on imaging modalities (ultrasonography, computed tomography scans, and magnetic resonance imaging) with high sensitivity, but steatohepatitis and fibrosis cannot be distinguished. Thus, an inherent drawback in studying the epidemiology of NAFLD is the lack of definitive laboratory tests, no uniform definition—with different studies using cut‐off values of alcohol consumption from <20 g/week to 210 g/week, and case selections where biopsy was used for definition. In studies outside the region, the prevalence of NAFLD varies from 16% to 42% by imaging, and 15–39% of liver biopsies. The major risk factors for NAFLD, central obesity, T2DM, dyslipidemia, and metabolic syndrome, are now widely prevalent and are increasing geometrically in the Asia–Pacific region. It is therefore not surprising that NAFLD is common in this region. Estimates of current prevalence range from 5% to 30%, depending on the population studied. Central obesity, diabetes, and metabolic syndrome are the major risk factors. To date, however, data on the natural history and impact of NAFLD causing serious significant chronic liver disease are lacking and there is a need for prospective, cooperative studies.

Asia-Pacific consensus guidelines on gastric cancer prevention

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.

Epidemiology of Helicobacter pylori Infection and Public Health Implications

This review summarizes studies on the epidemiology and public health implications of Helicobacter pylori published in peer‐reviewed journals from April 2010 through March 2011. Prevalence rates vary widely between different geographical regions and ethnic groups. An interesting study from the USA identified the degree of African ancestry as an independent predictor of H. pylori infection. Two studies have demonstrated early childhood as the period of transmission of infection and identified an infected sibling as an important risk factor. An oral–oral route of spread has been substantiated with several studies showing the presence of H. pylori in the oral cavity. Studies have shown the presence of H. pylori in drinking water and the role of poor living conditions and sanitation in H. pylori infection, supporting an oral–fecal route of spread. Screening for H. pylori as a gastric cancer pre‐screening strategy has been described in Japan, and the importance of H. pylori eradication as a gastric cancer–prevention strategy has now been further emphasized in Japanese guidelines. Two studies have shown a decrease in the burden of dyspepsia and peptic ulcer disease with H. pylori eradication.

Gastro-oesophageal reflux disease, reflux oesophagitis and non-erosive reflux disease in a multiracial Asian population: a prospective, endoscopy based study.

Objective To determine the prevalence of and risk factors for gastro-oesophageal reflux disease (GORD), reflux oesophagitis and non-erosive reflux disease (NERD) amongst Malaysian patients undergoing upper gastrointestinal endoscopic examination. Design A cross-sectional study on consecutive patients with dyspepsia undergoing upper gastrointestinal endoscopy. Setting A large general hospital in Kuala Lumpur, Malaysia. Participants Consecutive patients undergoing endoscopy for upper abdominal discomfort were examined for the presence of reflux oesophagitis, hiatus hernia and Barretts oesophagus. The diagnosis and classification of reflux oesophagitis was based on the Los Angeles classification. Patients with predominant symptoms of heartburn or acid regurgitation of at least one per month for the past 6 months in the absence of reflux oesophagitis were diagnosed as having NERD. The prevalence of GORD, reflux oesophagitis and NERD were analysed in relation to age, gender, race, body mass index (BMI), presence of hiatus hernia, Helicobacter pylori status, alcohol intake, smoking and level of education. Results One thousand patients were studied prospectively. Three hundred and eighty-eight patients (38.8%) were diagnosed as having GORD based on either predominant symptoms of heartburn and acid regurgitation and/or findings of reflux oesophagitis. One hundred and thirty-four patients (13.4%) had endoscopic evidence of reflux oesophagitis. Two hundred and fifty-four (65.5%) were diagnosed as having NERD. Hiatus hernia was found in 6.7% and Barretts oesophagus in 2% of patients. Of our patients with reflux oesophagitis 20.1% had grade C and D oesophagitis. No patients had strictures. Following logistic regression analysis, the independent risk factors for GORD were Indian race (odds ratio (OR), 3.25; 95% confidence interval (CI), 2.38–4.45), Malay race (OR, 1.67; 95% CI, 1.16–2.38), BMI > 25 (OR, 1.41; 95% CI, 1.04–1.92), presence of hiatus hernia (OR, 4.21; 95% CI, 2.41–7.36), alcohol consumption (OR, 2.42; 95% CI, 1.11–5.23) and high education level (OR, 1.52; 95% CI, 1.02–2.26). For reflux oesophagitis independent the risk factors male gender (OR, 1.64; 95% CI, 1.08–2.49), Indian race (OR, 3.25; 95% CI, 2.05–5.17), presence of hiatus hernia (OR, 11.67; 95% CI, 6.40–21.26) and alcohol consumption (OR, 3.22; 95% CI, 1.26–8.22). For NERD the independent risk factors were Indian race (OR, 3.45; 95% CI, 2.42–4.92), Malay race (OR, 1.80; 95% CI, 1.20–2.69), BMI > 25 (OR, 1.47; 95% CI, 1.04, 2.06) and high education level (OR, 1.66; 95% CI, 1.06–2.59). Conclusions Reflux oesophagitis and Barretts oesophagus were not as uncommon as previously thought in a multiracial Asian population and a significant proportion of our patients had severe grades of reflux oesophagitis. NERD, however, still constituted the larger proportion of patients with GORD. Indian race was consistently a significant independent risk factor for reflux oesophagitis, NERD and for GORD overall.

Asia-Pacific consensus on the management of gastroesophageal reflux disease: update.

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.