Fighting H. pylori gastric cancer through screening and surveillance in Asia-Pacific

Gastric cancer remains one of the world’s most lethal malignancies, ranking fifth in both incidence and cancer-related mortality, with an estimated 980,266 new cases and 641,554 deaths recorded in 2024. More than half of this burden falls on the Asia-Pacific region, particularly East Asia, where age-standardized incidence rates remain substantially higher than in Western countries. A comprehensive new review published in The Lancet Regional Health – Western Pacific argues that the region’s best weapon against this disease is not a single intervention but an integrated continuum of prevention—spanning primary prevention through Helicobacter pylori screening and eradication, secondary prevention through endoscopic detection of early cancers, and tertiary prevention through risk-stratified surveillance of patients who remain vulnerable even after the bacterium has been cleared. Written by Jeesun Yoon and Do-Youn Oh of Seoul National University, the review synthesizes national experiences from across the region to show how different health systems have adapted the same biological logic to wildly different epidemiological and economic circumstances.

The biological rationale for this approach rests on the well-characterized carcinogenic pathway known as the Correa cascade. Chronic H. pylori infection drives a multistep inflammatory process that progresses from chronic active gastritis to atrophic gastritis, intestinal metaplasia, dysplasia, and ultimately adenocarcinoma. Persistent inflammation induces oxidative stress, DNA damage, and genomic instability, while bacterial virulence factors such as CagA and VacA alter epithelial signaling and modulate host immune responses. Critically, infection-related epigenetic alterations—including aberrant DNA methylation of tumor suppressor genes—can persist even after the bacteria themselves are eradicated, creating a “field” of residual cancer susceptibility. This explains why eradication reduces but does not eliminate cancer risk, and why the timing of intervention matters: once irreversible mucosal damage has occurred, the so-called point of no return in the cascade, removing the bacterial trigger alone cannot restore the stomach to a low-risk state.

The strongest evidence for population-level eradication comes from Taiwan, which has served as the world’s proof-of-concept laboratory for the screen-and-treat model. Beginning in 2004, the Matsu Islands program targeted adults aged 30 and older in an isolated, high-risk community with population-based H. pylori testing and eradication. After ten years, the program had achieved a 78.7% reduction in H. pylori infection and a 77.2% reduction in atrophic gastritis, and long-term follow-up demonstrated a 53% reduction in gastric cancer incidence compared with the pre-intervention period. Taiwan has since expanded the strategy to all 55 indigenous townships and, in a stroke of pragmatic brilliance, embedded H. pylori stool antigen testing within its existing colorectal cancer screening program—leveraging established invitation systems and primary care networks. Although the primary intention-to-screen analysis of this pragmatic trial did not reach statistical significance, adjusted analyses showed a significant 21% reduction in gastric cancer incidence, and the program is scheduled for nationwide rollout in 2026 as part of Taiwan’s organized cancer screening services.

China has taken a different path toward the same goal, scaling population-based eradication across geographically heterogeneous high-risk regions rather than implementing a uniform national program. H. pylori prevalence in China varies enormously, from 51.3% in the northwest to 29.6% in the northeast, and this diversity has pushed policymakers toward community-based mass intervention in high-risk hotspots. The results have been striking. A landmark cluster-randomized trial involving more than 180,000 adults from high-risk rural communities—the largest population-based eradication program reported to date—demonstrated a significant reduction in gastric cancer incidence after a median follow-up of 11.8 years following a large-scale screen-and-treat intervention. Earlier randomized evidence from Linqu County had shown that no gastric cancer developed among participants without baseline premalignant lesions who received eradication, underscoring the biological imperative of intervening before irreversible damage sets in. Bhutan, meanwhile, has demonstrated that even a resource-limited health system can execute a nationwide program: through its government-led Health Flagship Program, more than 370,000 individuals underwent H. pylori screening, achieving over 90% coverage of the target population.

Not every country has embraced universal eradication, and the review makes clear that this reluctance is often epidemiologically and economically rational. Japan has instead woven H. pylori diagnosis and treatment into its long-standing gastric cancer prevention infrastructure, expanding national health insurance coverage for eradication therapy in 2013 so that treatment became widely accessible in routine practice. Japan was also the first country to approve the potassium-competitive acid blocker vonoprazan for eradication, which in a Phase 3 trial achieved a 92.6% eradication rate compared with 75.9% for conventional proton pump inhibitor-based triple therapy. South Korea, by contrast, delivers primary prevention through an integrated, endoscopy-based model in which testing and eradication are applied selectively to individuals with clinically or endoscopically defined risk—a strategy validated by a randomized trial showing that eradication in infected first-degree relatives of gastric cancer patients significantly reduced cancer risk. In lower-incidence countries such as Australia and Singapore, population-wide screen-and-treat is not cost-effective, and efforts focus on high-risk subgroups, including first-generation migrants from high-prevalence Asian countries and, in Singapore’s case, the ethnically Chinese population whose gastric cancer risk far exceeds that of Malay or Indian cohorts.

Across all these models, a common enemy has emerged: antimicrobial resistance. Resistance to clarithromycin, metronidazole, and levofloxacin has risen across much of the Asia-Pacific region, and this has driven considerable divergence in recommended first-line regimens. Countries with established molecular diagnostics, such as South Korea and Japan, increasingly recommend PCR-based susceptibility testing before treatment, reserving bismuth-containing quadruple therapy—typically a 10- to 14-day course of a proton pump inhibitor, bismuth, and two antibiotics—for situations where tailored therapy is not feasible. The review warns that prolonged adherence to clarithromycin-based triple therapy in regions where resistance already exceeds the 15% threshold has undermined eradication success, and it calls for affordable point-of-care molecular tests that would enable resistance profiling even in resource-limited settings, making tailored therapy available to the many rather than the few.

Because eradication alone cannot eliminate risk in people with established atrophic gastritis or intestinal metaplasia—conditions that confer a hazard ratio of 3.6 to 9.3 for subsequent gastric cancer—secondary prevention through endoscopic screening constitutes the second pillar of the continuum. South Korea operates one of the most intensive programs globally, offering biennial endoscopy to all citizens aged 40 and older through its National Cancer Screening Program. A nationwide nested case-control study of more than 16.5 million people found that participation reduced gastric cancer mortality by 21% overall, with endoscopic screening alone achieving a striking 47% mortality reduction, and mortality falling progressively with each additional screening round. Japan, which began nationwide radiographic screening in 1983, has been transitioning toward endoscopy; a large prospective cohort study showed that endoscopic screening reduced gastric cancer mortality by 61% and advanced cancer incidence by 22%, whereas radiographic screening, while reducing mortality, showed no effect on advanced disease incidence. These data have cemented endoscopy’s superiority and informed policy shifts in both countries.

The third pillar—risk stratification after eradication—is where the review makes its most forward-looking contribution. Residual cancer risk after successful eradication does not plateau but continues to rise linearly for more than a decade, and cancers have been detected more than 14 years after bacterial clearance. To manage this persistent threat, clinicians now deploy a multimodal toolkit. Histologically, the OLGA and OLGIM staging systems grade the severity and topographic extent of atrophy and intestinal metaplasia, with stage III or IV disease identifying patients who account for nearly all subsequent cancers and high-grade dysplasia. Endoscopically, the Kimura-Takemoto classification maps the atrophic border, with open-type atrophy signaling substantially elevated risk. Serologically, the Japanese ABC method combines anti-H. pylori antibodies with serum pepsinogen levels to triage patients non-invasively. Most intriguingly, emerging molecular biomarkers—particularly DNA methylation signatures that function as a molecular clock of cumulative carcinogenic exposure—may soon allow clinicians to identify individuals at exceptionally low residual risk, safely reducing unnecessary endoscopies, while concentrating surveillance on those with high methylation levels who remain at substantially increased risk despite favorable conventional features.

For patients who have already developed gastric neoplasia, tertiary prevention completes the continuum. Endoscopic submucosal dissection has become the standard treatment for selected early gastric cancers, preserving the stomach while achieving excellent oncologic outcomes, but the remaining mucosa frequently harbors extensive field cancerization. Two landmark randomized trials—one in Japan and one in South Korea—demonstrated that H. pylori eradication after endoscopic resection reduced metachronous gastric cancer by approximately 50%, establishing eradication as the standard of care in this setting while simultaneously proving that eradication alone is insufficient. Patients treated with ESD therefore require lifelong, risk-adapted endoscopic surveillance, with annual or biennial endoscopy commonly performed in high-incidence countries.

The authors conclude that the era of one-size-fits-all prevention is ending. As H. pylori prevalence falls and antimicrobial resistance climbs, the challenge is shifting from expanding eradication toward precision implementation—tailoring eradication regimens, screening intensity, and surveillance intervals to regional epidemiology, healthcare resources, and individual risk profiles. Upstream interventions also remain unfinished business: improving sanitation and clean water access, reducing household transmission, and developing an effective prophylactic vaccine, for which a Phase 3 trial of an oral recombinant vaccine in Chinese children showed promise in preventing infection but has not yet demonstrated cancer prevention. If the Asia-Pacific’s diverse national experiments can be coordinated into evidence-based continua of care, the review argues, a substantial share of the region’s gastric cancer burden—and the hundreds of thousands of deaths it causes each year—could ultimately be prevented.