Stomach cancer in the United States is the seventh most common cause of death from cancer. About 95 percent of all stomach cancer is gastric adenocarcinoma. Other, less common forms are lymphomas and leiomyosarcomas.

Adenocarcinoma is classified by how it looks:

• A pouch that juts out, like a polyp (A patient with this type of tumor has a better chance of survival than if the tumor is penetrating.)
  
• A sharp, well-defined border that may be ulcerated
  
• Spreading, which spreads across the surface of the lining of the stomach or into its walls
  
• Miscellaneous, which means the tumor shows chracteristics of two of the other types (Most fall into this category.)

In its early stage, stomach cancer has no specific symptoms. Both doctors and patients tend to dismiss any symptoms, often for months. Clues to the presence of stomach cancer include:

• Feeling full after a large meal, which is more likely if the cancer is blocking the region where the stomach empties into the intestines
  
• Pain, which may suggest peptic ulcer
  
• Loss of weight or strength due to not getting enough nutrients
  

Bleeding is rare, but it may cause anemia (low blood count). Occasionally the first symptom of stomach cancer is evidence of its having spread to other organs. This may lead to an enlarged liver, jaundice, fluid accummulation in the spaces between tissues and organs in the abdominal cavity, skin nodules and bone fractures.

The cause of stomach cancer is not yet known. Gastric ulcers are sometimes thought to lead to cancer. H. pylori, a bacteria that causes ulcers, may be a factor leading to stomach cancer.

Gastritis and intestinal metaplasia of the gastric mucosa are often found but are generally thought to be a result, rather than an early sign, of gastric cancer. Persons who have ulcers of the duodenum (the connection between the lower part of the stomach and the intestines) generally have a lower risk of getting stomach cancer.

One of the key elements of an accurate diagnosis is distinguishing stomach cancer from peptic ulcer and its complications. Some diagnostic procedures used include:

• Endoscopy, which allows the doctor to see the area and take samples of tissues from suspicious areas
• Examination of cells taken from the area or areas of concern
  
• Double-contrast X-ray techniques in which the inside of the stomach is coated with barium. The stomach is then inflated and examined using X-rays.
  

The earlier the tumor is found, the more effective treatment is. The more superficial the tumor is when found, the better the results of treatment. Treatment of primary lymphomas is more effective than treatment of gastric adenocarcinoma.
Treatment, depending on the nature of the tumor, may include:

• Surgery, which involves removing most or all of the stomach and adjacent lymph nodes. In some situations, when a patient's quality of life can be improved, surgery to bypass an obstructing tumor may be done.
  
• Combining chemotheraphy and radiation therapy, especially in gastric lymphoma
  
  

• Samuel Oschin Comprehensive Cancer Institute
• Cedars-Sinai Outpatient Cancer Center
• S. Mark Taper Foundation Imaging Center