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. Because other types of gastric cancer occur much less frequently, this article focuses on adenocarcinoma.

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 think 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 high part of the stomach where it connects with 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 that may be 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 history of pernicious anemia, a history of chronic atrophic gastritis, a condition of decreased gastric acid, and a prior history of adenomatous gastric polyp.

• Loss of appetite
• Difficulty swallowing, particularly difficulty that increases over time
• Vague abdominal fullness
• Nausea and vomiting
• Vomiting blood
• Abdominal pain
• Excessive belching
• Breath odor
• Excessive gas (flatus)
• Unintentional weight loss
• A general decline in health
• Premature abdominal fullness after meals

• An upper GI series showing gastric cancer
• An EGD (esophagogastroduodenoscopy) and biopsy showing gastric cancer
• A CBC showing anemia (although there are many other reasons for anemia)
• A stool test that is positive for blood

Surgical removal of the stomach (gastrectomy) is the only curative treatment. Radiation therapy and chemotherapy may be beneficial. A recent study showed that for many patients, chemotherapy and radiation therapy given after surgery improve the chance of a cure.

For patients in whom surgery is not an option, chemotherapy or radiation can improve symptoms. For some patients, a surgical bypass procedure may provide relief of symptoms.

There is a wide variation in prognosis of gastric tumors. Tumors in the lower stomach are more often cured than those in the higher area -- gastric cardia or gastroesophageal junction. The depth to which the tumor invades the stomach wall and whether lymph nodes are involved influence the chances of cure.

In circumstances in which the tumor has spread outside of the stomach, cure is not possible and treatment is directed toward improvement of symptoms.

• Cancer spreading (metastasizing) to other organs or tissues
• Weight loss
• Fluid accumulation in the belly (ascites)