Aug. 1 (Bloomberg) -- Eradicating the bacteria that causes ulcers may also reduce the risk of gastric cancer recurring, Japanese researchers said.

The chance of the cancer returning was cut by two-thirds after eliminating the germ, the scientists said in a study published in the Lancet medical journal. The bacteria are killed by Takeda Pharmaceutical Co.'s Prevacid, one of several heartburn medicines.

While scientists have known that removing the germ called Helicobacter pylori in laboratory animals can stave off malignancies, screening for the bacteria and treating it in people to prevent gastric cancer isn't generally accepted, the study said. About 21,500 cases will be diagnosed in the United States this year, according to the American Cancer Society, and 10,880 will die.

``There is better evidence that H. pylori eradication can prevent mortality than there is for colonoscopy screening'' for colorectal cancer, Nicholas Talley of the Mayo Clinic's site in Jacksonville, Florida, said in an accompanying editorial.

The Japanese researchers followed 544 patients who were given Prevacid and an antibiotic mix twice a day for a week or didn't receive any treatment. The patients were newly diagnosed and planning to have endoscopic treatment or were being watched after the removal of gastric cancer.

The researchers, led by Mototsugu Kago and Masahiro Asaka of the Hokkaido University Graduate School of Medicine, re-examined the patients after 6, 12, 24 and 36 months to see if cancer reappeared at a different site in the stomach. The risk of the malignancy returning was cut to 1.4 in 100 from 4 in 100, the study said.

The World Health Organization, based in Geneva, categorizes the germ as a class I carcinogen, meaning it is known to cause cancer.

To contact the reporter on this story: Eva von Schaper in Munich at evonschaper@bloomberg.net.

Last Updated: July 31, 2008 19:01 EDT