Data for this Review were identified by searches of PubMed from relevant articles using the search terms “gastric cancer”, “screening”, and “Asia”. Abstracts and reports from meetings were included only when they related directly to previously published work. Only papers published between 1995 and 2007, preferably in English, but also in Chinese, Japanese, and Korean, were included. Epidemiological data were further searched by GLOBOCAN 20023 and cancer registries or health reports of
ReviewScreening for gastric cancer in Asia: current evidence and practice
Introduction
Gastric cancer is the second most common cause of death from cancer worldwide,1, 2 and in many Asian countries, such as China, Japan, and Korea. Early gastric cancer (figure 1) is typically small and asymptomatic, and the high mortality from gastric cancer is mainly due to late presentation. Therefore, early detection and treatment is an important way to reduce death from gastric cancer. Nonetheless, screening for gastric cancer is not commonly practised and there is a paucity of data in Asia to lend support to such a programme.
To determine the current practice of gastric-cancer screening in Asia, experts on gastric cancer in the Asia Pacific region (including gastroenterologists, surgeons, and endoscopists) formed the Asia Pacific Working Group on Gastric Cancer. Experts from eight Asian countries—China, Japan, Korea, Malaysia, Philippines, Singapore, Taiwan, and Thailand—were invited to join the working-group meeting in Cebu, Philippines, during Asia Pacific Digestive Week in November, 2006, to discuss the epidemiology, screening, and prevention of gastric cancer. The working group was supported by the World Organisation of Digestive Endoscopy (OMED) and Asian Pacific Society of Digestive Endoscopy (APSDE).
Before the meeting, participants completed a written-opinion survey on screening for gastric cancer, which included questions on who to screen, when to screen, and how to screen. Eradication of Helicobacter pylori and cost-effectiveness of screening were also discussed during the meeting.
This Review summarises the working group's discussion. We also present epidemiology for gastric cancer and the current approaches to gastric-cancer screening in Asian countries that have high incidence of the disease.
Section snippets
Epidemiology of gastric cancer in Asia
Asia covers a large geographical area: it has more than 40 countries and diverse ethnic groups. Socioeconomic conditions, political status, and health-care systems vary widely between different Asian countries. We extracted the cancer incidence in Asian countries from GLOBOCAN 2002 of the WHO's database.3 Figure 2 and table 1 summarise the incidence of gastric cancer in men. Generally, countries in east Asia (including Japan, Korea, and China) have high incidence of gastric cancer (ie, >40
Risk factors for gastric cancer
An understanding of the risk factors associated with gastric carcinogenesis is important for identifying high-risk groups that may need screening, particularly in countries where mass screening is not practised.
Familial aggregation of gastric cancer
Gastric cancer tends to cluster in families. The risk of stomach cancer is increased at least 1·5-times in siblings or offspring of patients with stomach cancer.24, 25 In addition to genetic factors, the clustering of H pylori in family members may be an important contributory factor.26, 27, 28 In a case-control study from Hong Kong,29 the prevalence of H pylori in first-degree relatives of patients with gastric cancer was 1·8-times (95% CI 1·3–2·5) higher than age-matched and sex-matched
Screening guidelines in Asia
Apart from countries such as Japan and Korea where gastric cancer is highly prevalent, many Asian countries generally have no national guidelines or recommendations for gastric-cancer screening. Whether screening, especially that of the mass population, should be done remains controversial.
China
Although gastric cancer is the second most common cancer in China, there is no nationwide screening programme. Early detection of gastric cancer therefore relies on opportunistic screening only. Although endoscopy is widely available in major cities, availability and accessibility in rural areas is limited. The cost of upper-gastrointestinal endoscopy is low compared with that in developed countries, but it might not be affordable to less-privileged citizens. Barium-meal studies and
Cost-effectiveness
There is paucity of data for the cost-effectiveness of a mass screening programme for gastric cancer, even from Asian countries with high prevalence of the disease. A study from Singapore35 suggested that screening endoscopy every 2 years for a moderate to high-risk population (eg, Chinese men aged 50–70 years) is highly cost effective in the health-care system. Therefore, endoscopy screening in targeted high-risk populations might be more cost effective than mass screening in countries with
Conclusion
Although the incidence of gastric cancer is declining in most developed countries, it remains one of the most common causes of cancer-related death in Asia. Screening and early detection play a pivotal part in reducing mortality from this cancer. However, mass screening for gastric cancer, particularly by endoscopy, may not be the most practical approach because of reasons such as acceptance, availability, and cost. Multistage screening by serum-pepsinogen testing or H-pylori serology, or both,
Search strategy and selection criteria
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