In the May 1 issue of Cancer Research, researchers say their study results should lay to rest any question about whether ¨C and when -- antibiotic treatment of H. pylori can eliminate or reduce risk of developing gastric, or stomach cancer.

"We concluded that H. pylori eradication prevented gastric cancer to the greatest extent when antibiotics were given at an early point of infection, but that eradication therapy given at a later time point also delayed the development of severe lesions that can lead to cancer," said the study's lead author, James Fox.

The findings are important, Fox says, because stomach cancer is the second leading cause of cancer death worldwide, and approximately half of the world's population is infected with H. pylori.

Although H. pylori infection is now recognized as the major cause of both peptic ulcers and gastric cancer, and has been classified as a group I carcinogen by the World Health Organization, physicians are not sure whom to screen and treat with costly antibiotics, aside from first degree relatives of gastric cancer patients and those with peptic ulcer disease, he adds.

Fox's research team examined the effects of treating and eliminating H. pylori at different stages of progression from gastritis, an inflammation of the mucous membrane layer of the stomach, to development of gastric cancer.