Eradicating a Killer Stomach Bug

Stomach cancer bacterium H pylori eradication success affected by various factors

(RxWiki News) You don’t hear much about stomach (gastric) cancer in this country. But cancer of the stomach is the second leading cancer-related death in the world. Researchers are looking at ways to prevent this cancer altogether.

Helicobacter pylori (H. pylori) – a type of bacteria – is a risk factor for gastric cancer. A new study has found that the kind of antibiotic used to eradicate H. pylori isn’t the only important factor to success. Where a person lives, sticking with the antibiotic therapy and return of infection may be equally important to dealing with H. pylori.

"See a doctor if you get nauseous after eating."

Douglas R. Morgan, MD, MPH, of Vanderbilt Medical Center in Nashville, Tennessee led a study to assess how well three antibiotic regimens worked. The team estimated the risk of H. pylori returning and what factors were related to successfully eliminating the bacterium one year after treatment.

Study background information indicated that gastric cancer rates are estimated to increase over the next several decades because of an aging population and prevalence of the disease in some areas of the world. Latin American and eastern Asia have the greatest incidence of gastric cancer.

The researchers reported that more than half of the world’s population has been infected with H pylori. Chronic infection is associated with about two-thirds of gastric cancer cases worldwide.

For this study, nearly 1,500 people between the ages of 21 and 65 from seven Latin American cities were enrolled. The individuals were randomly assigned to receive one of three treatment regimens and were observed for nearly two years following the therapy.

The regimens each involved a combination of antibiotics given either together or sequentially over various time periods. The three groups were made up of people who received: 14 days of lansoprazole, amoxicillin and clarithromycin (triple therapy); 5 days of lansoprazole and amoxicillin followed by 5-day lansoprazole, clarithromycin, and metronidazole (sequential); or 5 days of lansoprazole, amoxicillin, clarithromycin and metronidazole (concomitant - given at the same time).

The overall risk of the bacterium returning (recurrence) ranged from 6.8 percent in people from Costa Rica to 18.1 percent in Colombia. Recurrence a year after treatment was most affected by where the person lived, how many children lived in the household and non-adherence (not taking correctly) to the therapy.

The type of treatment given was not a significant factor in the success rate. Researchers found that the overall success rate was 79.3 percent. Specific success rates were 80.4 percent for triple therapy, 79.8 percent for sequential therapy and 77.8 percent for concomitant therapy.

“In our current study, adherence, study site, sex, and age were significantly associated with the probability of a successful one-year outcome. From the public health perspective, a ‘one size fits all’ intervention strategy may not be optimal,” the authors wrote.

The researchers concluded, “Ongoing research initiatives are needed, given the expected increase in the gastric cancer burden in Latin America over the next two decades, evidence that H. pylori infection is the dominant risk factor, and evidence that eradication reduces gastric cancer risk.”

This study was published in the February 13 issue of JAMA. The research was supported by the Bill & Melinda Gates Foundation and the National Institutes of Health. No conflicts of interest were disclosed.

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Review Date: 
February 12, 2013