The specific treatment for a stomach infection may be less important than how well people stick with it. That's one conclusion of a new study on treatment of Helicobacter pylori infection. H. pylori bacteria are linked with stomach inflammation (gastritis) and ulcers. Long-term infection also increases the risk of stomach cancer. The new study included 1,463 adults from Latin America. All were infected with H. pylori. They were randomly divided into groups. The groups took different combinations of antibiotics for 5 to 14 days. Tests one year later showed nearly 80% were free of the infection. Rates were similar for all treatment groups. For about 11% of those who had successful treatment at first, the infection came back. H. pylori was most likely to return if people didn't take their medicines exactly as prescribed. Men, older adults and people who lived in particular countries also were more likely to have the infection return. The Journal of the American Medical Association published the study. MedPage Today wrote about it February 13.

By Robert H. Shmerling, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Did you know that some infections can increase your risk of cancer?

It's true. These cancers have well-established links with infections:

• Cervical cancer with human papilloma virus (HPV)
• Gastric (stomach) cancer with Helicobacter pylori (H. pylori) bacteria
• Liver cancer with hepatitis B or C virus, if infection is chronic (long-lasting)

There are likely to be other examples not yet discovered.

We don't have effective ways to prevent many types of cancer. But those linked to infection are different. If we can detect and treat the infection, cancer may be prevented. Even more effective is prevention of the infection in the first place. That's the strategy behind the HPV vaccine.

This new study examines treatments for H. pylori. Effective treatment is important because gastric cancer is the second leading cause of cancer death worldwide. Understanding what works in the treatment of H. pylori could lower rates of gastric cancer. It could also lower the rate of a potentially dangerous stomach inflammation (called gastritis) and ulcers. H. pylori increases the risk of those problems as well.

This new study enrolled more than 1,400 people with H. pylori infection from 7 Latin American communities. Each was assigned to 1 of 3 treatment groups. Treatment included various combinations of antibiotics. People also took a medicine to reduce stomach acid. Treatment lasted 5 to 14 days.

Overall, the failure rate of a single treatment course was about 27%. This included a group (11% of people in the study) who had successful treatment at first but then become infected again.

Interestingly, the results were similar regardless of the treatment. However, having the infection come back after a single course of treatment was linked with other factors. These included:

• Where people lived – For example, re-infection after successful treatment varied from 7% in Costa Rica to 18% in Columbia.
• Not taking the medicines as prescribed
• Male gender
• Age

These results show something common in medical care. The success of a treatment may depend more on features of the patient (such as age or gender) than the particular treatment. In this research, the particular medicines mattered less than whether the person actually took them as recommended.

In the end, a 27% failure rate is too high. This research points out several needs:

• Better treatments for H. pylori
• Treatments that people are willing to take as prescribed
• A better understanding of why treatments fail

What Changes Can I Make Now?

For most people, H. pylori infection can't be prevented. Good hand washing can reduce spread from person to person. However, more than half of the world's population is already infected with this bacterium. Most never have a problem despite the medical problems linked to it.

If you have symptoms that could be caused by ulcers or stomach inflammation related to H. pylori, see your doctor. These symptoms may include:

• Upper abdominal (stomach) pain
• Nausea and vomiting
• Poor appetite
• Weight loss
• Black or bloody stools

If you have an ulcer or other digestive problem related to H. pylori, you are likely to be prescribed antibiotics and anti-acid medicines. This new research shows how important it is to take your medicines as prescribed.

You also can take other steps that may reduce your risk of developing stomach cancer.

• Eat lots of vegetables and fresh fruits.
• Don't smoke.
• Drink only moderate amounts of alcohol.
• Cut back on foods that are smoked, cured, fermented or pickled.

What Can I Expect Looking to the Future?

Testing for H. pylori is recommended now primarily for people with suspected gastritis, ulcers or gastric cancer. But that could change. In the future, we may learn that screening healthy people for H. pylori is a good idea, especially in some parts of the world. Infection is particularly common in Latin America and eastern Asia. Based on research that is going on now, we may have better treatments for H. pylori in the near future.

Just a few years ago, the idea that an infection might lead to cancer was just a theory. Now we know that several common cancers have a strong infectious connection. It seems likely that other types of cancer will be discovered to be linked with infections.