Bacterial infection may cut esophageal cancer risk

People who aren't infected with Helicobacter pylori have a "markedly increased" risk of developing esophageal cancer, a new study shows. However, the findings don't address the issue of whether or not the bacterium should be eradicated, lead author Dr. Catherine de Martel of Stanford University School of Medicine and her colleagues note.

"It's a bad bug, but what we show in this study is that it's not a bad bug in everybody, and perhaps we have to be careful and think a little bit more before we try to treat everybody," de Martel told AMN Health.

Some research has found a negative association between H. pylori and gastroesophageal reflux disease (GERD), and while H. pylori infection is declining in the developed world, esophageal cancer is on the rise, de Martel and her team note in The Journal of Infectious Diseases.

Researchers have suggested that H. pylori may decrease gastric acidity in some people with the infection, thereby reducing the risk of reflux disease and esophageal cancer, de Martel's group notes.

To investigate the association further, they conducted a study of 128,992 health system members who had undergone a health checkup during the 1960s.

During follow-up, which lasted from 5 to 35 years, 52 patients developed esophageal cancer. These 52 patients were matched to three control patients without cancer, and serum samples that had been collected at the checkup were evaluated for antibodies to H. pylori.

The risk of developing esophageal cancer during the follow-up period was 80 percent lower in H. pylori-positive subjects compared with those who were not carriers, the researches found. The effect was only statistically significant among individuals who were younger than 50 at the time of the check-up, and was not influenced by cigarette smoking or body mass index, other esophageal cancer risk factors.

While this study is not the first to link esophageal cancer to the absence of H. pylori infection, de Martel told Reuters Health, "what is new is the fact that this study has a very strong methodology; it's a big cohort, and they have been followed prospectively."

"H. pylori is one of myriad organisms that chronically inhabit the human body, but this single organism may simultaneously increase the risk of development of ulcers, gastric cancer and gastric lymphoma and decrease the risk of development of esophageal (cancer) and GERD," the authors conclude.

They believe future studies and cost-benefit analyses "will ultimately identify the healthiest balance between humans and H. pylori."

SOURCE: The Journal of Infectious Diseases, March 1, 2005.