Treating Helicobacter pylori (H pylori) infection markedly reduces the risk for stomach cancer, a large study from Kaiser Permanente Northern California (KPNC) demonstrates.
People with H pylori who were treated had about a 63% lower risk of developing noncardia gastric adenocarcinoma (NCGA) after 8 years of follow-up compared with peers with H pylori who were not treated.
The US data align with previous studies, conducted mostly in Asia, that found that treating the infection can reduce stomach cancer incidence.
The KPNC study shows the “potential for stomach cancer prevention in US populations through H pylori screening and treatment,” study investigator Dan Li, MD, gastroenterologist with the Kaiser Permanente Medical Group and Kaiser Permanente Division of Research in Oakland, California, told Medscape Medical News.
Judith Kim, MD, a gastroenterologist at NYU Langone Health in New York City, who wasn’t involved in the research, told Medscape Medical News that the study is significant because “it is the first to show this effect in a large, diverse population in the US, where gastric cancer incidence is lower.”
The study was published online May 2 in Gastroenterology.
Top Risk Factor
About 30% of people in the United States are infected with H pylori, which is the number one known risk factor for stomach cancer, Li said.
The study cohort included 716,567 KPNC members who underwent H pylori testing and/or treatment between 1997 and 2015.
Among H pylori-infected individuals (based on positive non-serology test results), the subdistribution hazard ratio (sHR) was 6.07 for untreated individuals and 2.68 for treated individuals, compared with H pylori-negative individuals.
It’s not surprising that people who were treated for the infection still had a higher risk of NCGA than people who had never had the infection, Li said.
“This is likely because many people with chronic H pylori infection had already developed some precancerous changes in their stomach before they were treated. This finding suggests that H pylori ideally should be treated before precancerous changes develop,” he said.
When compared directly with H pylori positive/untreated individuals, the risk for NCGA in H pylori positive/treated individuals was somewhat lower at < 8 years follow-up (sHR 0.95) and significantly lower at 8+ years of follow-up (sHR 0.37).
“After 7 to 10 years of follow-up, people with H pylori who received treatment had nearly half the risk of developing stomach cancer as the general population,” Li said. “This is likely because most people infected with H pylori in the general population are not screened nor treated. This highlights the impact screening and treatment can have.”
The data also show that cumulative incidence curves for H pylori positive/untreated and H pylori positive/treated largely overlapped during the first 7 years of follow-up and started to separate after 8 years.
At 10 years, cumulative NCGA incidence rates for H pylori positive/untreated, H pylori positive/treated, and H pylori negative were 31.0, 19.7, and 3.5 per 10,000 persons, respectively (P < .0001).
This study shows that treating H pylori reduces stomach cancer incidence in the United States, thus “filling an important research and knowledge gap,” Li said.
In the United States, Asian, Black, and Hispanic adults are much more likely to be infected with H pylori, and they have a two- to threefold higher risk of developing stomach cancer, he noted.
“This suggests it may be reasonable to consider targeted screening and treatment in these high-risk groups. However, the optimal strategy for population-based H pylori screening has not been established, and more research is needed to determine who should be screened for H pylori and at what age screening should begin,” Li said.
Strong Data, Jury Out on Universal Screening
For additional comment, Medscape Medical News reached out to Aaron Glatt, MD, a spokesperson for the Infectious Diseases Society of America (IDSA) and chief of infectious diseases and hospital epidemiologist at Mount Sinai South Nassau in Oceanside, New York.
The study shows that the treatment of H pylori “absolutely will decrease your risk of certain types of gastric carcinoma down the line. It does take a while to show that, 7 years, but this study shows that very clearly,” Glatt said.
“People who have definitely been shown to have H pylori should be treated,” Glatt told Medscape Medical News.
“I don’t think this study yet supports that everybody should be screened, but it does make sense that people who have upper GI symptoms consistent with H pylori should be checked for H pylori and then appropriately treated, he noted.
Routine screening for H pylori is recommended in countries with high incidence of gastric cancer, but not in the United States, Kim noted.
“Given the risk reduction of cancer with H p ylori treatment, consideration should be made in the US for asymptomatic individuals with a family history of gastric cancer or immigrants from high-incidence countries,” she added.
The study was funded by the Kaiser Permanente Northern California Community Health Research Grants Program, The Permanente Medical Group Delivery Science & Applied Research Program, and The Permanente Medical Group. Li, Glatt, and Kim have declared no relevant financial relationships.
Gastroenterology. Published online May 2, 2023. Abstract
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