Taipei: Adding a one-time test for a common stomach bacterium to Taiwan's existing colorectal cancer screening program could generate societal benefits worth five times the cost while cutting gastric cancer deaths, a study led by National Taiwan University Hospital (NTUH) has found.

According to Focus Taiwan, the study suggests that most cancer screening programs require additional spending to achieve health benefits and extend lives. Lee Yi-chia, a clinical professor in NTUH's Department of Internal Medicine, emphasized that the two-in-one strategy could "extend lives while also saving money." The study was published online in the Journal of the American Medical Association (JAMA) on June 1.

The proposed approach involves screening for colorectal cancer and Helicobacter pylori (H. pylori) infection using the same stool sample. Taiwan has been conducting biennial fecal immunochemical testing (FIT) for eligible adults as part of its colorectal cancer screening program since 2004. As of January 1, 2026, Taiwan became the first country to offer a one-time H. pylori stool antigen test alongside FIT nationwide for people aged 45-74, aimed at detecting the bacterium, a leading cause of gastric cancer.

The strategy has led to 605,579 asymptomatic individuals in Taiwan undergoing the H. pylori antigen test by July 15, a significant increase from the 109,205 screened in the previous 20 years. Decades of research, including a 10-year randomized trial in Changhua County, provided evidence that the combined testing could reduce gastric cancer incidence.

Lee highlighted that H. pylori is a carcinogen, increasing the risk of developing gastric cancer by six times. The bacterium can be detected through a breath or stool test and treated with antibiotics. Without population-based screening, gastric cancer is often detected at advanced stages, leading to higher fatality rates. In 2025, gastric cancer accounted for 2,225 deaths in Taiwan, making it the country's eighth-leading cause of cancer death.

The two-in-one strategy aims to increase engagement in H. pylori screening for gastric cancer prevention, considering cost-effectiveness as a critical factor for public policy implementation. Data from a clinical trial in Changhua County involving about 240,000 people were used to model health outcomes and societal costs for a hypothetical cohort over 30 years. The strategy was projected to reduce gastric cancer mortality by 13.5% and produced a benefit-cost ratio of 5.08, indicating substantial societal benefits.

Lee noted that the initial costs of screening and antibiotic treatment could be offset over time by avoiding expenses related to gastric cancer surgery and other treatments. The strategy remains cost-effective at an H. pylori prevalence of at least 17%, below the current rate of about 22% among the targeted age group. The findings suggest that the strategy is most applicable in regions with similar gastric cancer incidence and established colorectal cancer screening programs.

Internationally, Lee's work has influenced global guidance. He was among experts convened by the World Health Organization's International Agency for Research on Cancer to develop 2025 guidance on H. pylori screen-and-treat programs for gastric cancer prevention. Taiwan's real-world evidence informed the guidance, including discussions on the two-in-one stool-testing approach. This involvement is significant as Taiwan has faced exclusion from the World Health Assembly, yet Lee has contributed to shaping WHO-linked global health guidance.