Dec. 8, 2000 -- The same bug that causes stomach ulcers may be responsible for setting off a chain of events that leads to stomach cancer. Researchers say giving the same combination of drugs used to combat ulcers may be a simple way to shrink stomach abnormalities and prevent them from progressing to cancer.
"We think the inflammation produced by the infection is what drives everything," says Pelayo Correa, MD. "My personal opinion is there is strong evidence that curing the infection will reduce the risk of cancer."
In a new study published in the Dec. 6, 2000 issue of Journal of The National Cancer Institute, Correa and colleagues found that almost 41% of people they studied had a decrease in the size of precancerous stomach abnormalities after taking the three-drug combination to eliminate the bug. In contrast, only 14% of people who still had the bug at the end of the study saw any decrease in the size of their stomach abnormalities.
The bug in question is Helicobacter pylori, or H. pylori, which has been fingered as the culprit in causing stomach ulcers. When given as an anti-ulcer therapy, the three-drug combination -- two antibiotics plus the main ingredient in Pepto-Bismol -- wipes the bug out of a person's system in about two weeks.
Correa, a pathologist at Louisiana State University Health Sciences Center in New Orleans, says some vitamins also may be important. In his study of more than 600 people from an area of South America with a high rate of stomach cancer, people who took the three-drug combination alone or in combination with vitamin C and/or beta carotene were three to five times more likely than people who received no treatment to have a reduction in the size of precancerous stomach abnormalities. People in the study who received only antioxidant vitamins -- either vitamin C and beta-carotene alone or together -- also showed improvement.
"You can prevent some of the damage caused by the inflammation by giving the antioxidants," Correa explains. "But the basic mechanism by which we think the cancer is being generated involves infection with H. pylori in the stomach." He says the antioxidants may be important for people who don't get enough natural antioxidants in their diet.
The study, which is the first of several investigating the link between the H. pylori bug and stomach cancer, "provides important leads" for researchers trying to come up with ways to prevent cancer, according to William J. Blot, PhD.
"These results are encouraging, but they're not the last word," says Blot, director of the International Epidemiology Institute in Rockville, Md. "We need more information before making strong recommendations."
Blot also says one cannot rule out the possibility that giving vitamins alone may be as effective as the anti-ulcer therapy since people who got only vitamins did have reductions in stomach abnormalities.
Several similar studies are ongoing, including a large study in China that is expected to have results soon. In addition to anti-ulcer medications and vitamins, that trial is also testing the possibility that garlic may help reduce some of the stomach abnormalities or prevent them from worsening. Correa says the results of that trial and others will help experts determine who should be treated with the prevention strategies and which of the strategies work best.
He says the most likely candidates are people with a family history of stomach cancer and those who live in areas where poor diet is common. But, Correa says the latter group could include a lot of people. In Colombia, where his study was conducted, 90% of people are infected with H. pylori -- 50% of them by age two.