H. pylori infection may protect against esophageal cancer

By lowering levels of stomach acid, infection with Helicobacter pylori may reduce the risk of adenocarcinoma of the oesophagus, according to study findings presented here on Tuesday at Digestive Disease Week 2003.

Individuals carrying H. pylori “were significantly less likely than uninfected subjects to get oesophageal adenocarcinoma,” lead author Dr. Catherine de Martel, from Stanford University in California, told reporters.In the study, the researchers reviewed the medical records of nearly 130,000 subjects who were followed since the 1960s. Fifty-two of the patients went on to develop oesophageal cancer.The researchers looked for signs of H. pylori in past blood samples from the patients and compared the results to those of 551 controls who never developed cancer. According to Dr. de Martel, individuals infected with H. pylori had a 72% lower risk of developing oesophageal cancer than uninfected individuals. This finding held even after researchers adjusted for other cancer risk factors such as age, gender, obesity, and history of smoking.How might H. pylori reduce oesophageal cancer risk? H. pylori infection is known to reduce the acid-secreting ability of the stomach. Because oesophageal adenocarcinoma is typically preceded by chronic acid reflux, infection with H. pylori may reduce the risk of this malignancy.These findings may leave patients and physicians in a bind as to whether they should eradicate H. pylori. Although the current findings argue against eradication, Dr. de Martel said she cannot recommend this strategy because H. pylori infection is also a known risk factor for ulcers and stomach cancer.But she said physicians should become more aware of the possible heightened risk of oesophageal cancer among patients with reflux disease who also test negative for H. pylori.The absolute risk for oesophageal adenocarcinoma remains very low –about 10 cases in every 100,000 individuals per year. But rates for the disease are rising.”In the 25 last years, there has been an almost 10-fold increase of this cancer in white males,” Dr. de Martel pointed out. She believes that the increasing use of antibiotics to eradicate H. pylori in Western populations may be behind this trend.(Source: Reuters Health: May 21, 2003: Oncolink)