Stomach Cancer: Causes and Diagnosis
There are several causes of stomach cancer. To name a few are previous exposure to radiation, bacterial infection caused by Helicobacter pylori, pernicious anemia, stomach surgery, as well as genetic factors that cause predisposition to the disease. Helicobacter pylori infections now thought to be responsible for most cases of stomach cancer involving the bottom half of the stomach. Stomach cancer near the junction between the esophagus and the stomach is not usually related to Helicobacter pylori infection.
Stomach cancer is a very serious condition. Symptoms usually arise later due to the large capacity of the stomach and often the tumor is not curable at the time of diagnosis. It is for this reason that the mortality rate for patients diagnosed with stomach cancer is exceedingly high. In the Far East, the incidence of stomach cancer remains high, probably due to the high rate of Helicobacter pylori infection, as well as certain dietary factors. Nobody knows for sure why the incidence of stomach cancer is decreasing in the United States. Lowe infection rates with Helicobacter pylori, known carcinogen and cause of stomach cancer, may be a partial explanation. However, other factors are probably also important.
Because the incidence of stomach cancer is relatively low in the United States, the American Cancer Society does not recommend routine endoscopic screening for the tumor as they do for colon cancer. Early diagnosis can occasionally be achieved if warning signals such as intestinal bleeding are immediately investigated. Many people over the age of 50 are having their stool checked for blood on an annual basis. If blood is found, it is generally recommended that the patient have a colonoscopy. If the examination would show up negative, however, an upper endoscopy examining the esophagus, stomach and duodenum (the first part of the small intestine) may clinch the diagnosis. While most of the patients will have esophagitis, gastritis, or peptic ulcer disease, an unsuspected stomach cancer may be found. Not infrequently, precancerous changes in the stomach lining are found at the time of endoscopy.
Chronic infection with Helicobacter pylori in some susceptible individuals causes a change in the lining of the stomach to resemble the small intestines (intestinal metaplasia). The risk of stomach cancer after acquiring intestinal metaplasia in the stomach is not nearly as great as that seen with Barrett’s esophagus (a precancerous condition of the esophagus). Therefore, it is currently not recommended that patients with this precancerous change in the stomach be endoscoped on a regular basis. Nevertheless, it is recommended that patients have an endoscopy every five to ten years after discovering intestinal metaplasia.
Anyone experiencing satiety should have an upper gastrointestinal series or endoscopy to rule out stomach cancer, especially if they are over the age of 45. Anyone who has multiple family members with stomach cancer should be checked for Helicobacter pylori infection and some gastroenterologists recommend a screening endoscopy in this situation. Stomach cancer may run in families, either because the members of the family are genetically susceptible to the disease or because the members of the family have infected each other with Helicobacter pylori.