Ulcer Bug May Protect
Against Cancer of Esophagus
Excerpt By E.J. Mundell, Reuters Health

By lowering levels of stomach acid, a common bacterium responsible for ulcers and many stomach cancers may, conversely, cut the risk of another killer -- cancer of the esophagus.

What's more, the finding may explain why cases of esophageal cancer have increased in white males in recent years, researchers say.

A large percentage of adults worldwide carry Helicobacter pylori bacteria in their gut. In recent decades, science has pinpointed H. pylori as the main cause of stomach ulcers, prompting doctors to recommend antibiotic eradication of the bug for patients with ulcers.

But now a study led by Dr. Catherine de Martel, of Stanford University in California, suggests that eradicating H. pylori may leave patients more vulnerable to a leading form of esophageal cancer.

Individuals carrying the ulcer bug "were significantly less likely than uninfected subjects to get esophageal adenocarcinoma," according to de Martel. She spoke to reporters here Tuesday at Digestive Disease Week, the largest annual gathering of gastroenterologists in the world.

In the study, the Stanford team pored over the medical records of about 130,000 California patients followed since the 1960s. Fifty-two of the patients went on to develop adenocarcinoma of the esophagus. The researchers looked for signs of H. pylori in blood samples collected from each of those patients in decades past, and compared the results to those of 551 "controls" who had never developed the cancer.

According to de Martel, individuals infected with H. pylori had about a 70 percent lower risk of developing the cancer, compared with uninfected individuals. This finding held even after researchers adjusted for other risk factors such as age, gender, obesity and history of smoking.

How might H. pylori reduce esophageal cancer risk -- even as it raises risks of ulcers and stomach cancer? De Martel noted that esophageal adenocarcinoma is almost always related to acid reflux disease, otherwise known as gastroesophageal reflux disease, or GERD.

Over time, acid washing up because of GERD can damage the esophagus until a condition called Barrett's esophagus arises. Almost all patients with esophagheal adenocarcinoma have a previous history of GERD and Barrett's esophagus, she said.

But H. pylori may damage the acid-secretion abilities of the stomach. This means that people with H. pylori may have less acid reflux, greatly reducing their esophageal cancer risk.

However, these findings may leave patients and physicians in a bind as to whether they should eradicate H. pylori.

Because the bacteria are responsible for both ulcers and stomach cancer, de Martel said: "I can't say 'don't eradicate H.pylori."' But she said doctors should become more aware of the possible heightened risk of esophageal cancer among patients with GERD who also test negative for the ulcer bug.

The absolute risk for adenocarcinoma of the esophagus remains very low -- about 10 cases in every 100,000 individuals per year. But rates for the illness are rising.

"In the 25 last years, there has been an almost 10-fold increase of this cancer in white males," de Martel pointed out. She believes that the increasing use of antibiotics to eradicate H. pylori in Western populations may be behind this trend.

Reference Source 89

For more information on how to prevent other diseases, use
PreventDisease.com's "Quick Prevention Resources".