Chronic infection with the bacteria Helicobacter pylori is the strongest known risk factor for gastric, or stomach, cancer. Importantly, it's a preventable risk factor, treatable using a combination of antibiotics and proton pump inhibitors (PPIs), which reduce the amount of acid produced in the stomach.

Regardless of its preventability, there has been an alarming rise in stomach cancer in people under 50. Now, research led by the International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO), has projected the future incidence of stomach cancer, including cases attributable to H. pylori infections, among people born between 2008 and 2017.

The researchers first used large-scale modeling to estimate the future burden of stomach cancer, assuming there were no changes in current prevention or treatment strategies. Then they estimated how many of those cases are linked to H. pylori. National, age-specific incidence rates were pulled from GLOBOCAN 2022, a global cancer statistics database, with mortality projections coming from the United Nations. The simulation model estimated how many people will develop cancer during their lifetime based on how often the cancer occurs at different ages, how likely people are to die before they can develop cancer, and demographic trends like population growth and aging.

If current treatment practices were to continue unchanged, based on these simulations, it's expected that during the lifetime of all men and women born between 2008 and 2017, there will be 15.6 million new gastric cancer cases globally. Of those cases, 76% – or three-quarters – are attributable to infection with H. pylori and are therefore potentially preventable. Asia is projected to bear the highest burden, with 10.6 million cases, followed by the Americas (2 million) and Africa (1.7 million cases).

A 100% effective H. pylori screening and treatment program could reduce cases by up to 75%. Even programs that are 80% to 90% effective would still prevent between 60% and 68% of stomach cancer cases. These strategies are cost-effective, the researchers said, even in lower-income settings, and comparable to vaccination campaigns for human papillomavirus (HPV) or hepatitis B.

"A shift in focus toward the life course of today's young people and their prospects of developing gastric cancer, with or without interventions, underscores the need for greater investment in gastric cancer prevention, including the implementation of population-based H. pylori screen-and-treat strategies," said the researchers.