Pilot Study Suggests Certain Bacteria May Increase Risk of Stomach Cancer
Stomach cancer, also known as gastric cancer, is one of the leading causes of cancer deaths throughout the world according to the World Health Organization, with as many as three-quarters of a million deaths attributed to stomach cancer every year.1
Although it’s not as common in the United States as it is in some countries, there are still approximately 75,000 people in the U.S. who are currently diagnosed with stomach cancer, and about 20,000 new cases are reported every year.
There’s a strong case that obesity and smoking may cause gastric cancer. In addition, a recent pilot study indicates that a bacteria [known as Helicobacter pylori (H. pylori)] also may be linked to stomach cancer. Although this specific bacterial strain does not affect every patient in the same way, according to researchers. The study also found many types of bacteria to be beneficial.2
What is Gastric Cancer?
The function of the stomach is to process foods that have been eaten and help remove waste material from the body. The stomach walls are comprised of multiple tissue layers. When malignant cells form in any of these layers, the result is gastric cancer. Stomach cancer can occur in any part of the stomach and can spread throughout the entire stomach. If it becomes metastasized, it can spread to other parts of the body.
There are five stages of gastric cancer:
- Stage 0: In this stage, abnormal cells are discovered in the innermost portions of the stomach. These cells may become malignant and spread. Stage 0 is also referred to as carcinoma in situ.
- Stage I: This stage is subdivided into Stage IA and Stage IB. In Stage IA, cancer may have spread into adjacent portions of the stomach. In Stage IB, cancer may have spread into the lymph nodes or to the muscle layer.
- Stage II: Stage II is subdivided into Stage IIA and Stage IIB. In Stage IIA, cancer may have spread to several lymph nodes or to some of the tissue that is adjacent to the stomach wall’s muscle layer. In Stage IIB, cancer may have spread to as many as 15 lymph nodes or to the outermost layers of the stomach.
- Stage III: Stage III Is subdivided into Stage IIIA, Stage IIIB, and Stage IIIC. In Stage IIIA, cancer may have spread to other organs such as the colon, liver, or kidneys. In Stage IIIB, cancer may have spread to the back of the abdomen. In Stage IIIC, cancer may have spread to additional body organs.
- Stage IV: In Stage IV, cancer has spread to other body parts such as the liver and the lungs. It also may have spread to distant lymph nodes.
Symptoms of Gastric Cancer
During the initial phases of the disease, symptoms may include general stomach discomfort, indigestion, and feeling bloated. Early symptoms also may include heartburn, mild nausea, and loss of appetite.
As the disease progresses into the later stages, symptoms often include stomach pain, vomiting, blood in the stool, and unexplained weight loss. Other late-phase symptoms often include trouble swallowing, jaundice, and a build-up of fluid in the abdomen known as Ascites.
What’s Helicobacter Pylori?
H. pylori is a spiral-shaped bacterium and it’s known to cause ulcers and is suspected of being a contributing factor in stomach cancer. Researchers believe that infections like H. Pylori may be responsible for as much as 20 percent of all cancers on a worldwide basis, either directly or indirectly.3
In a recent study in East Asia, it was found that while a particular strain of H. pylori containing a gene known as cagA was present in both cancer and non-cancer participants, only about 70 percent had cagA allele, an East Asian gene which has been significantly linked to gastric cancer.4
Additionally, the median H. pylori load in the cancer group was six times higher than the load in the non-cancer group. This may help to explain why patients in certain geographical regions tend to be more susceptible to stomach cancer. These findings could lead to improvements in screening techniques and better treatment options.
The H. Pylori infection can be spread in a number of ways, including contaminated water or food. However, it’s important to know that most people who have H. Pylori in their stomach do not develop stomach cancer. There is even some evidence that the presence of H. Pylori may lower the risk of stomach cancer in certain groups of people.
Reducing the Risk
There are four tests that are commonly used to detect H. pylori in the stomach and small intestine. 5 A blood antibody test checks to see whether a patient’s blood has formed antibodies, indicating that the patient is currently infected or has been infected in the past. A urea breath test checks for the presence of H. pylori in a patient’s stomach. This test also is useful in determining whether a treatment has been successful.
A stool antigen test checks to see if the stool contains a substance that the immune system uses to fight an H. pylori infection. Like the urea breath test, this test can help determine the effectiveness of treatments previously administered. A stomach biopsy can be used to confirm or deny the presence of H. pylori in the stomach and the small intestine.
When these tests confirm the presence of the H. pylori bacteria, the condition usually can be cured with antibiotic treatment. Because of this, anyone who is worried about getting the H. pylori infection should speak to their doctor.
Treating Gastric Cancer
According to the pilot study, H. pylori has been present in several gastric cancer cases and as a result, it may contribute to cancer progression. If gastric cancer does progress, there are five main treatment. Here is a brief discussion of each:
- Surgery: Surgery often is used to remove a portion of the stomach that has suffered damage as the result of cancer. This may stop the disease before it develops into a later stage. However, surgery carries a risk of infection and bleeding. Also, a person who has a major portion of their stomach removed may suffer digestive issues.
- Chemotherapy: Chemo may be able to destroy cancer cells or reduce the size of a tumor so that it can be removed. It also may be used following surgery to remove any remaining cancer cells. However, chemo has side effects that may be severe depending on the particular drugs that are used.
- Targeted drugs: Certain drugs can be used to target and kill cancer cells within the stomach. These drugs often are used in combination with other treatments such as chemo. While such an approach can be highly successful, side effects may be dramatic.
- Radiation: Radiation therapy uses X-rays or other high-powered energy beams to kill cancer cells. While such a treatment can be highly effective, it can cause nausea, vomiting, indigestion, and diarrhea.
- Immunotherapy: Immunotherapy is one of the most exciting new therapies to come along in a long time. 6 Also called biologic therapy, it works in such a way as to boost the body’s natural ability to fight the disease. Although techniques are new and under development, it’s believed that the side effects will be very minor when compared to other therapies.