H. pylori treatment in Asia tied to lower risk of gastric cancer 10+ years later

Last Updated: 2018-03-29

By Marilynn Larkin

NEW YORK (Reuters Health) - Treatment of Helicobacter pylori infection is associated with a lower risk of gastric cancer 10 or more years after treatment, even when treatment is provided to older people, researchers say.

In Hong Kong, the age at gastric cancer diagnosis is "usually quite high," at 68 for women and 71 for men, according to Dr. Wai Leung of the University of Hong Kong and colleagues.

"While H. pylori-associated gastric cancer development is a very long process, it is generally believed that eradication at young age is more effective for gastric cancer prevention and there may be a point of no return," Dr. Leung told Reuters Health by email.

"However," he said, "our study showed that eradication could still significantly reduce the gastric cancer risk in individuals who received H. pylori therapy at age 60 and older when compared to general population."

"The reduction in risk is more apparent 10 years or more after treatment in the older age groups," he said, "supporting the benefits of earlier treatment."

As reported online March 14 in Gastroenterology, Dr. Leung and colleagues analyzed data on more than 73,000 individuals in Hong Kong infected with H. pylori who received eradication therapy with clarithromycin (median age at therapy, 55; 47% men).

They compared the gastric cancer incidence in this cohort with the expected incidence for the general population, matched for age and sex. Age-stratified groups were: less than 40 years old, 40-59, and 60 or older.

Overall, 200 patients (0.27%) developed gastric cancer during a median followup of 7.6 years.

Compared with the matched general population, the gastric cancer risk was significantly lower in patients 60 years or older who had received H. pylori treatment (standardized incidence ratio, 0.82), but not in younger groups.

When data were stratified based on time from H. pylori treatment (less than 5 years, 5-9 years, and 10 or more years), compared with other age groups, the risk of gastric cancer was significantly lower than the general population 10 or more years after eradication among the 40-59 year-olds (SIR, 0.32) and those 60 and older (SIR, 0.42).

Notably, the relative risk of gastric cancer was significantly higher in males who received H. pylori treatment at age 60 or older than in age-matched females (RR 1.8).

A total of 13.4% of patients needed retreatment, and the overall relative risk of gastric cancer among those patients was twice that of those who were not retreated (RR, 2.0). The relative risk for middle-aged (40-59 years) individuals who required re-treatment was 2.5.

Dr. Aziz Aadam of Northwestern University Feinberg School of Medicine in Chicago told Reuters Health, "It was previously unknown if treating H. pylori in an older population of patients would be helpful once precancerous changes develop and whether treatment altered the feared consequence of H. pylori-associated gastric cancer."

The study results showed that H. pylori eradication "is vital to the prevention of H. pylori-associated gastric cancer and is also beneficial in older patient populations," he said by email.

"One caveat is that the patients in this study are from Hong Kong and the results may not be as applicable in western countries, which have a lower risk of gastric cancer," he said. "Additionally, the protection afforded by H. pylori eradication can be compromised with antibiotic resistance."

Another recent study (http://bit.ly/2u6vSvp) showed that H. pylori eradication lowers the risk of recurring gastric cancer.

SOURCE: http://bit.ly/2J5JnhZ

Gastroenterology 2018.