Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started
My Medicine

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cancer Health Center

Font Size

H. Pylori Has Mixed Role in Cancer

Ulcer Bacterium Raises Risk of Some Stomach Cancers, Lowers Others
WebMD Health News
Reviewed by Louise Chang, MD

Oct. 17, 2006 -- A bacterium that causes ulcers also increases the risk of cancer of the lower stomach, but it seems to protect against cancer of the upper stomach that includes the junction of the esophagus, researchers from the National Cancer Institute report.

The seemingly paradoxical findings may help explain the changing incidence of these cancers in the industrialized world.

Helicobacter pylori bacterial infection has been on the decline in the United States and other industrialized countries over the past decades, due to improved sanitation and the introduction of antibiotic drugs.

This decline has been accompanied by a dramatic drop in lower stomach cancers and, more recently, an equally dramatic rise in cancers of the junction between the lower esophagus and upper stomach.

"These cancers were basically nonexistent in the U.S. 30 years ago," NCI researcher Farin Kamangar, MD, PhD, tells WebMD. "During the past 20 years or so there has been a 350% increase in the rates of these cancers among white males in this country."

Threefold Lower Risk

In an effort to better understand the role of H. pylori in stomach cancerstomach cancer, Kamangar and colleagues recruited 468 Finnish people participating in a larger cancer prevention trial and tested their blood for evidence of the gut bacteria. Half of the 468 had stomach cancer, and half did not. The patients were recruited for the trial between the mid- to late-1980s.

As expected, those who tested positive for H. pylori had a higher risk of developing cancer of the lower stomach. Their risk was found to be almost eight times higher than study participants with no history of H. pylori infection.

Somewhat more surprising, the risk of developing cancer of the upper stomach including the junction to the esophagus was three times lower among participants who tested positive for H. pylori infection.

The findings are published in the October issue of the Journal of the National Cancer Institute.

One theory is that H. pylori infection helps protect against junctional cancer by reducing the esophagus' exposure to stomach acid, Kamangar says.

Acid reflux Acid reflux involves the backup of stomach acid into the esophagus. Chronic acid reflux can cause a condition called Barrett's esophagus, which is a risk factor for esophageal cancer.

Today on WebMD

Colorectal cancer cells
New! I AM Not Cancer Facebook Group
Lung cancer xray
See it in pictures, plus read the facts.
sauteed cherry tomatoes
Fight cancer one plate at a time.
Ovarian cancer illustration
Real Cancer Perspectives
Jennifer Goodman Linn self-portrait
what is your cancer risk
colorectal cancer treatment advances
breast cancer overview slideshow
prostate cancer overview
lung cancer overview slideshow
ovarian cancer overview slideshow
Actor Michael Douglas