Stomach cancer, also called gastric cancer, is a malignant cell growth that begins in the cells of the stomach and invades the surrounding healthy cells.  Stomach cancer is less common in the United States than in some other countries. In the past, it was one of the leading causes of cancer deaths in the U.S. However, the incidence of the disease has declined due to possible improvements with food handling and storage and better treatment of infections.

The stomach is a sac-like digestive organ located in the abdomen that is composed of five layers.  The innermost layer, called the mucosa, is the most common site for the start of stomach cancer.  From the mucosa, it can spread into the outer layers of the stomach lining and beyond to other tissues and organs.

Adenocarcinoma takes up 90 to 95 percent of stomach cancer cases, according to the American Cancer Society (ACS). This cancer develops from the glandular cells of the innermost lining (mucosa).  Other less common stomach cancers can develop in lymph tissue (lymphoma), hormone-producing cells (carcinoid tumors) or certain nerve cells (gastrointestinal stromal tumors or GIST).

The causes of stomach cancer are unknown but diet and certain bacteria infections have been strongly linked to the disease. In addition, smoking and obesity are considered risk factors for stomach cancer. Age plays a role in stomach cancer susceptibility with two-thirds of the cases occurring in individuals 65 years of age and older. Lifestyle and dietary changes can significantly impact a person’s risk of developing this cancer.

The signs and symptoms of stomach cancer rarely appear in the early stages of the disease. For this reason, stomach cancer often goes undetected until the later stages. The signs and symptoms of the disease can include abdominal pain, indigestion, bloating and unexplained weight loss. As the disease progresses, patients may develop jaundice and exhibit blood in their stools.

Diagnosis typically involves compiling the patient’s medical history, physical examination, blood tests, stool tests (e.g., fecal occult blood test) and imaging tests such as CAT scan and MRI. Biopsies of the suspected tissue are taken to identify cell type and rate of growth.

Treatment for stomach cancer often involves surgery, usually a partial or a total gastrectomy (removal of stomach tissue), as well as chemotherapy and radiation therapy. In many patients, treatment will use a combination of these therapies.

The overall 5-year survival rate for individuals with stomach cancer in the United States is about 23 percent, according to the ACS. The relatively low survival rate is due to the difficulty in detecting the cancer in its early stages. If stomach cancer is found and treated early, the 5-year survival rate increases to nearly 60 percent. In addition, cancers located in the lower portion of the stomach tend to have a better survival rate than those in the upper section. Early detection significantly improves the prognosis (outlook) for individuals diagnosed with this disease.