That heartburn or sour stomach you are experiencing may be an early warning sign. Upper digestive problems can be a precursor to something much worse. Gastric cancer, also known as stomach cancer, kills up to a million people annually worldwide. Scientists still do not fully understand why some people get gastric cancer and others don’t but recent research has provided clues about how some stomach cancers form.
Helicobacter pylori, the bacterium linked to ulcers, have been implicated in stomach cancers, including adenocarcinoma and gastric mucosa-associated lymphoid tissue (MALT) lymphoma.
A stomach ulcer is an open sore in the stomach and or small intestine that can form when H. pylori bacteria, particularly certain subtypes, convert some of the chemicals in some foods into chemicals that cause mutations or changes in the DNA of the cells in the stomach lining. This may explain why certain foods, preserved meats for example, increase a person's risk for stomach cancer. Likewise, some of the foods that lower stomach cancer risk contain antioxidants, which can block substances that damage a cell's DNA.
Most cases of H. pylori infection are often longstanding. Such an infection typically produces no signs or symptoms, but symptoms can occur, including stomach pain or burning, nausea, vomiting, frequent burping, bloating and weight loss. It is recommended if you have any of these symptoms for two weeks or more you should seek medical care. Your health care provider will decide if testing for the infection is prudent.
A longstanding H. pylori infection can lead to chronic inflammation of the stomach, which can result in loss of normal gastric tissue and replace it with intestinal and fibrous tissues. This transformation of the normal stomach tissue increases the risk for cancer development, said Dr. Neena S. Abraham, a gastroenterologist at the Michael E. DeBakey V.A. Medical Center and associate professor of medicine at the Baylor College of Medicine in Houston.
“H. pylori alone does not lead to stomach cancer; other factors, like genetic susceptibility, are also necessary for the condition to develop,” she said.
In certain ethnic groups and in developing countries where there is a high occurrence of H. pylori infection, modified screening and surveillance programs have been adopted to identify and treat the cancer at an early, curable stage.
In Japan, for example, early detection and eradication of H. pylori in combination with esophagogastroduodenoscopy (or EGD, a scope procedure to examine the upper digestive tract), has reduced the death rates associated with gastric cancer. However, it has been estimated that to screen 5 to 6 million Japanese citizens annually, the cost of such a program exceeds $300 million.
“In the United States, where H. pylori is on the decline, we have no current national recommendations for routine EGD screening or surveillance. We are still learning a lot about the connection between H. pylori infection and gastric cancer,” Dr. Abraham said.
H. pylori are primarily passed from person to person through direct contact with saliva or fecal matter. H. pylori can also be spread through untreated water. The bacteria enter your body through your mouth and passes into your digestive system.
The stomach and its hyper-potent stomach acid make a hostile environment for many bacteria, but the H. pylori bacterium is especially well adapted for survival in the stomach. It produces an enzyme that, through a series of biochemical processes, creates a low-acid buffer zone for itself and could be one reason infections are longstanding.
An area of active research is looking at the effect of H. pylori eradication on people at high risk for ulcers over time. Studies are ongoing to examine the type and extent of damage to normal stomach tissue in patients who have had H. pylori that has been eradicated. However, without further research it remains unclear if eradication of H. pylori eliminates entirely a person’s risk of gastric cancer.
The National Cancer Institute, part of the National Institutes of Health, has more information on stomach cancer and H. pylori infection: http://www.cancer.gov/cancertopics/factsheet/risk/h-pylori-cancer
Lynette Summerill, is an award-winning journalist who lives in Scottsdale, Arizona. In addition to writing about cancer-related issues, she writes a blog, Nonsmoking Nation, which follows global tobacco news and events.