Stomach cancer, among the most common cancers worldwide, occurs primarily in patients between 65 and 80 years of age. In the United States, doctors diagnose some 28,000 people with stomach cancer each year, more often in men than in women.
People of all cultures can develop stomach cancer, but it is more frequently diagnosed in people of African, Hispanic and Indigenous descent in the U.S., and in Eastern Europeans, East Asians and South Americans worldwide. By country, the disease is more common in North and South Korea, Japan, China, Southern and Eastern Europe, and Central and South America. It’s less common in North America, Northern and Western Africa, and South Central Asia.
There are multiple kinds of stomach cancer, with adenocarcinoma making up the majority, or more than 90% of stomach cancers. Adenocarcinoma develops in the cells of the stomach’s lining, or mucosa. Another type of this disease is stomach lymphoma, a cancer of the immune system tissue found in the stomach wall. Gastrointestinal stromal tumors (GIST) are rare tumors that form in the stomach wall. And carcinoid tumors begin in the hormone-making cells of the stomach. Other cancers, including small cell carcinoma and leiomyosarcoma, are very rare but also might start in the stomach.
Stomach cancer’s most common symptoms — indigestion, bloating and overall stomach discomfort — make diagnosing this disease difficult. These symptoms affect many of us from time to time, but if they persist, you should contact your physician.
While doctors aren’t certain exactly what causes stomach cancer, they know there are many contributing factors that increase the risk of it occurring. In addition to age, gender and ethnicity, the following factors may increase a person’s risk for stomach cancer:
- Obesity. Being overweight or obese is a possible cause of cancer of the cardia (the upper part of the stomach nearest the esophagus). Also, low levels of physical activity — not exercising — increases the risk of stomach cancer.
- Diet. Eating a diet high in meat and other food that is smoked, salted or pickled increases risk. However, eating lots of fresh fruit and vegetables appears to lower the risk.
- Smoking. Smokers are more likely than nonsmokers to develop stomach cancer, particularly in the upper portion of the stomach near the esophagus. The rate of stomach cancer is nearly doubled in smokers, and heavy smokers face the greatest risk.
- Helicobacter pylori (H. pylori) infection. This bacterial infection in the stomach lining can progress to stomach cancer. As many as two-thirds of the world’s population harbors H. pylori in their stomachs, and while most don’t become ill, the bacterium causes most peptic ulcers and other stomach and upper small-intestine ulcers. If you have upper abdominal pain or persistent indigestion, get tested for H. pylori, which can be eradicated with antibiotics.
- Long-term stomach inflammation, that occurs with conditions like pernicious anemia or as an autoimmune condition called atrophic gastritis.
- Prior gastric surgery, even many years after the procedure. These operations include surgeries done for peptic ulcer disease called Billroth I and II, and procedures that remove part of the stomach.
- Family history of stomach cancer among first-degree relatives (parents, siblings or children). The more cases, the greater your risk.
- Inherited genetic mutation. Some types, known as diffuse stomach cancers, are believed to be potentially inheritable. Talk to your doctor about the stomach cancers in your family or contact our Clinical Genetics Service at Roswell Park to set up an appointment with a genetic counselor.
Never miss another Cancer Talk blog!
Sign up to receive our monthly Cancer Talk e-newsletter.Sign up!
To decrease your risk of stomach cancer, you should maintain a healthy weight, eat a diet full of fresh fruits and vegetables, eliminate or limit the amount of salty and smoked foods, and exercise regularly.
If you smoke, you need to quit. One study linked smoking to as many as one in five cases of stomach cancer. Find support and guidance by calling the New York State Smokers’ Quitline at Roswell Park, at 1-866-NY-QUITS (1-866-697-8487), or visit www.nysmokefree.com for more information.