76% of gastric cancer cases could be prevented

Around 15.6 million people born between 2008 and 2017 worldwide could develop gastric cancer at some point in their lives and, according to a study published in the journal ' Nature Medicine ', many of these could have been prevented since 76% of these cases can be attributed to Helicobacter pylori , a common bacterium found in the stomach. If more and better gastric cancer prevention measures had been in place, particularly through population-wide H. pylori screening and treatment programs.

According to this work, in Spain the number of people at risk in individuals born between 2008 and 2017 is 4,720,818 and the number of expected cases of gastric cancer, if there are no changes in the current gastric cancer control measures, would be 58,641, of which 44,436 would be attributable to H. pylori.

Gastric cancer is a complex disease with a significant global health burden. Although its incidence has declined in industrialized countries, it remains the fifth most common cancer and the fifth leading cause of cancer death worldwide. Its geographic distribution is uneven , with high rates in East Asia and parts of Latin America, and low rates in Western countries.

The main risk factor is infection with Helicobacter pylori, classified by the WHO as a class I carcinogen . This bacterium infects more than half of the world's population and can cause chronic gastritis , which in some cases progresses to gastric cancer.

The study suggests that most of these cases could be prevented through H. pylori screening and treatment programs, which could reduce incidence by up to 75%. However, few countries have implemented these strategies on a large scale.

This paper examines data on gastric cancer incidence in 185 countries in 2022, combined with cohort-specific mortality projections from United Nations demographic data.

According to their estimates, 15.6 million people worldwide born between 2008 and 2017 are likely to be diagnosed with gastric cancer during their lifetime, and that 11.9 million (76%) of those cases will be attributable to H. pylori infection.

The report details that the majority of cases occur in Asia, 10.6 million, with 6.5 million cases in India and China alone . In contrast, although sub-Saharan Africa currently has a relatively low burden of gastric cancer, projections suggest that its future burden could be at least six times higher than the 2022 estimates suggest.

However, by modeling the impact of H. pylori screening and treatment strategies at the population level, Park and his coauthors found that the predicted number of gastric cancers could be reduced by up to 75%.

For Luis Bujanda, professor of medicine at the University of the Basque Country (UPV/EHU), the article offers nothing new to what is already known and, he tells Science Media Centre, "I think it falls short of expectations regarding Helicobacter pylori or gastric cancer prevention."

Bujanda states that the Helicobacter pylori vaccine, which has been talked about for decades, has played an important role, but to date, there is nothing effective in eradicating or preventing the infection.

This expert explains that the incidence of gastric cancer is influenced by two very important factors. "One is Helicobacter pylori. As the article states, three-quarters of gastric cancers are directly related to Helicobacter pylori, although it's probably more, and that's something we already know. The other important factor is nutritional and dietary factors and genetic predisposition ."

And while developing countries have, on the one hand, worse hygiene and health conditions and higher prevalence of Helicobacter pylori, above 50-60%, in Western countries such as Spain and others, "the prevalence of Helicobacter pylori has dropped dramatically and is now below 35%."

However, Asunción García, from the Aragón Health Research Institute , clarifies that, although H. pylori is the main cause, "other factors such as alcohol, tobacco, obesity, sedentary lifestyle and genetic predisposition also influence."

Therefore, he adds, "a comprehensive approach to gastric cancer prevention strategies is required."