Cancer of the stomach, also called gastric cancer, is a disease in which malignant (cancer) cells arise from the lining of the stomach.
Stomach cancer can develop in any part of the stomach and then may spread throughout the stomach and to other organs. Stomach cancers are classified according to the type of tissue from which they originate. The most common type of stomach cancer is adenocarcinoma, which starts in the glandular tissue of the stomach, and accounts for 95% of all stomach cancers. Other forms of stomach cancer include lymphomas, which involve the lymphatic system, and sarcomas, which involve the connective tissue (such as muscle, fat, or blood vessels).
Stomach cancer can often be cured if it is found and treated at an early stage. Unfortunately, the outlook is poor if the cancer is already at an advanced stage.
What causes stomach cancer?
The exact cause of stomach cancer is unknown, but a number of conditions can increase the risk of the disease. Helicobacter pylori (H. pylori) infection of the stomach increases the risk of stomach cancer. H. pylori is a bacteria that infects the lining of the stomach and causes chronic inflammation and ulcers.
What are the symptoms of stomach cancer?
In the early stages of stomach cancer, a patient may have very few symptoms. Symptoms may include indigestion and stomach discomfort, a bloated feeling after eating, mild nausea, loss of appetite, or heartburn. These symptoms are similar to the symptoms caused by a hiatal hernia or peptic ulcer and may be treated with antacids or histamine blockers for temporary relief. Consequently, patients may not recognize these as serious symptoms and may not go to the doctor for a long time. A gastric tumor can grow very large before it causes other symptoms.
In more advanced stages of stomach cancer, a patient may have the following symptoms:
- Discomfort in the upper or middle part of the abdomen
- Blood in the stool (which appears as black, tarry stools)
- Vomiting or vomiting blood
- Weight loss
- Pain or bloating in the stomach after eating
- Weakness or fatigue associated with mild anemia
Who is at risk for stomach cancer?
There has been a significant decrease in the number of stomach cancer cases in the past 60 years, but it is still the seventh leading cause of cancer deaths in the United States. Various medical conditions can be associated with an increased risk of developing stomach cancer, including gastritis, pernicious anemia, gastric polyps, and gastric (peptic) ulcer. A person's risk of developing stomach cancer has been found to be greater if he or she has been infected with H. pylori bacteria.
There is a slightly increased risk of stomach cancer in people who use tobacco or drink alcoholic beverages regularly. Workers in certain industries are also at greater risk, including those in the coal, mining, nickel refining, rubber, and timber processing industries. Workers exposed to asbestos fibers are also at greater risk.
Stomach cancer is found most often in people who are over age 55, and affects men more than women. Stomach cancer is more common in Japan, Korea, parts of Eastern Europe, and Latin America than it is in the United States and Canada. This is thought to be related to the common diet in these countries, which consists of foods (especially meat and fish) preserved by drying, smoking, salting, or pickling, which contain nitrates and salt. Eating fresh foods, especially fruits and vegetables, may offer some protection against the disease.
How is stomach cancer diagnosed?
Some abnormalities may be found by your physician during a physical exam, but these findings generally indicate advanced stomach cancer. Some of these findings include enlarged lymph nodes, enlarged liver, and increased fluid in the abdomen (ascites).
When a patient has some of the initial vague symptoms, such as indigestion, weight loss, nausea, and loss of appetite, the doctor may order screening tests. These tests include:
- Upper GI series. These are X-rays of the esophagus and stomach (the upper gastrointestinal, or GI tract) after the patient drinks a barium solution. The barium outlines the stomach on the X-ray, helping the doctor find tumors or other abnormal areas.
- Gastroscopy and biopsy. This test examines the esophagus and stomach using a thin, lighted tube called a gastroscope, which is passed through the mouth to the stomach. Through the gastroscope, the doctor can look directly at the inside of the stomach. If an abnormal area is found, the doctor will remove some tissue (biopsy). A biopsy is the only sure way to diagnose cancer. Gastroscopy and biopsy are the best methods of identifying stomach cancer.
How is stomach cancer treated?
Stomach cancer may be treated with the following, alone or in combination:
- Surgery, called gastrectomy, to remove all or part of the stomach, as well as some of the tissue surrounding the stomach. Lymph nodes near the stomach are also biopsied to check for cancer cells. Lymphoma of the stomach is more frequently treated by gastrectomy than is adenocarcinoma of the stomach. Only about one-third of stomach cancer cases can be treated and cured surgically.
- Chemotherapy
- Radiation therapy
- Biological therapy (natural substances are used to boost the body's immune system to fight certain illnesses)
Cancer of the stomach is difficult to cure unless it is found at an early stage (before it has spread). Unfortunately, because early stomach cancer has few symptoms, the disease is usually advanced when the diagnosis is made. However, advanced stomach cancer can be treated and the symptoms can be relieved.
