Stomach cancer
Stomach cancer (also known as gastric cancer) is a disease in which the cells forming
the inner lining of the stomach become abnormal and start to divide uncontrollably,
forming a mass or a tumor.
General information about Stomach cancer
Stomach cancer is the seventh most common cancer in the United States. The American
Cancer Society (ACS) estimates that 23,000 new cases of stomach cancer will be diagnosed
in 1998 and about 14,000 people will die of the disease. Stomach cancer is much more
common in countries such as Japan, Chile, Costa Rica, Hungary, and Poland. It is a leading
cause of cancer deaths in many countries in central Asia, central Europe, and central and
South America. In the United States, there has been a dramatic drop in the incidence of
stomach cancer in the last 50 years. While the exact reason for this decline is not known,
it may be related to a decreased use of salting and smoking foods as a means of preserving
them and an increased use of refrigeration.
The disease is three times more common in men than in women. It is generally found in
people who are 40 years or older. The average age at first diagnosis is 60 years.
The stomach is a J-shaped organ that lies in the abdomen, on the left side. The
esophagus (or the food pipe) carries the food from the mouth to the stomach. The stomach
produces many digestive juices and acids that mix with the food and aid in the process of
digestion. The stomach is divided into five sections. The first three are together
referred to as the proximal stomach, and produce acids and digestive juices, such as
pepsin. The fourth section of the stomach is where the food is mixed with the gastric
juices. The fifth section of the stomach acts as a valve and controls the emptying of the
stomach contents into the small intestine. The fourth and the fifth sections together are
referred to as the distal stomach. Cancer can develop in any of the five sections of the
stomach. The symptoms and the outcomes of the disease may vary depending on the location
of the cancer.
Several different types of cancer can occur in the stomach. The
most common type is called adenocarcinoma, which refers to the way the cancer looks under
the microscope. There are several types of adenocarcinoma. Other types of gastric cancer
occur much less frequently so this article is focused on adenocarcinoma of the stomach.
Adenocarcinoma of the stomach is a common cancer of the digestive tract worldwide,
although it is relatively uncommon in the US. It occurs most frequently in men over 40
years old. The incidence of this form of gastric cancer is extremely high in Japan, Chile,
and Iceland. The incidence of most types of gastric adenocarcinoma in the US has declined
over the years. Experts propose that the decrease may be related to reduced intake of
salted, cured, and smoked foods and increased vitamin C consumption.
However, the incidence of adenocarcinoma in the proximal parts of the stomach (the
gastric cardia and gastroesophageal junction, where the stomach meets the esophagus) has
increased markedly, along with an increase in cancers of the lower esophagus. The reason
for this increase is unknown.
Diagnosis is often delayed by the absence of symptoms in early disease or by
self-treatment of symptoms, some of which are common to other, less serious
gastrointestinal disorders (bloating, gas, and a sense of fullness).
Risk factors for gastric cancer are a family history of gastric cancer, Helicobacter pylori
infection, blood type A, a personal history of pernicious anemia, a history of chronic
atrophic gastritis, a condition of decreased
gastric acid, and a prior history of adenomatous gastric polyp.
Causes of Stomach cancer
While the exact cause for stomach cancer has not been identified, having poor
nutritional habits, eating a lot of cured, pickled or smoked foods, eating foods high in
starch and low in fiber, smoking, drinking alcohol, and vitamin A deficiency are believed
to be risk factors for stomach cancer. Being male, African-American, and over 40 years of
age can also increase the risk of developing the disease.
Several studies have identified a bacterium (Helicobacter pylori) that causes stomach
ulcers (inflammation in the inner lining of the stomach). Chronic (long-term) infection of
the stomach with these bacteria may lead to a particular type of cancer (lymphomas or
mucosa-associated lymphoid tissue (MALT)) in the stomach.
People who have had previous stomach surgery for ulcers or other conditions may have a
higher likelihood of developing stomach cancers, although this is not certain. Another
risk factor is developing polyps, benign growths in the lining of the stomach. Although
polyps are not cancerous, some may have the potential to turn cancerous. |