Stomach cancer often referred to as gastric cancer, is a malignant cell disease or cancer that occurs in the lining of the stomach, which is an organ in the upper abdomen that helps digest food. The upper gastrointestinal tract, including the stomach and the esophagus, is very susceptible to cancers that begin in the mucus-producing cells inside the walls of these organs.
Although stomach cancer is declining in prevalence in North America, it is much more common in other areas of the world such as in Asia and the Middle East.
Definition & Facts
Most stomach cancers are adenocarcinomas, which means that they begin in the inner lining of the stomach. Other types of gastric cancer include gastrointestinal carcinoid tumors, gastrointestinal stromal tumors and lymphomas. Several rarer forms of cancer, such as squamous-cell carcinoma, small-cell carcinoma, and leiomyosarcoma, may begin in the stomach but are not traditionally grouped with other stomach cancers.
Stomach cancer usually affects older people, and the average age for a stomach cancer diagnosis in the United States is 69. The decline in stomach cancer cases in the developed world is generally attributed to food storage and refrigeration technology, increased use of antibiotics and decreased levels of sodium in food.
Symptoms & Complaints
- Feeling full or bloated after eating a small amount of food
- Severe and persistent heartburn and indigestion
- Nausea or persistent vomiting
- Stomach pain
- Dramatic and unintentional weight loss
Many patients also complain of a vague discomfort in the abdomen just above the naval, or even see a clear indication of fluid build-up near the stomach. Unfortunately, many of these symptoms are caused by diseases or ailments other than cancer, such as untreated ulcers or various stomach viruses.
In most stomach cancer cases, the cancer has already spread to other parts of the body before it is even diagnosed. Doctors typically commission tests if patients complain of three or more of these symptoms and have certain risk factors in their medical history.
There is a general distinction in medical literature between causes and risk factors, but the two are often conflated in cancer studies. Risk factors for stomach cancer include tobacco use; diets that consist of smoked foods, salted fish, and pickled vegetables; obesity; the previous presence of cancers including lymphoma; and pernicious anemia, particularly in patients with type A blood. While the presence of one or more of these factors in a person's medical history certainly increases the likelihood that they will develop stomach cancer, doctors are unsure of precisely which factors lead definitively to cancer.
The spiral-shaped bacterium Helicobacter pylori has proven important in stomach cancer studies due to its disproportionate presence in affected patients. Several tests have concluded that there is a strong association between H. pylori infection and the risk of non-cardia gastric cancer. However, cancer only begins when a mutation occurs in the genetic makeup of a cell that causes it to multiply and divide at a rapid rate rather than dying -- this means that the presence of H. pylori alone is not enough to cause gastric cancer. Several pre-cancerous conditions in the stomach lining are currently being researched as possible causes as well, including intestinal metaplasia and chronic atrophic gastritis.
Diagnosis & Tests
A doctor typically will diagnose stomach cancer based on medical history knowledge and symptoms. If he or she decides that cancer is a likely option, the patient will be referred to a gastroenterologist, a doctor who specializes in gastrointestinal disease for further testing.
Gastroenterologists often use imaging tests to determine whether cancerous cells are present in the stomach lining. These tests include CT scans and special types of X-rays often referred to as barium swallows.
The main test used to diagnose stomach cancer is called an upper endoscopy. This test consists of the doctor inserting a thin, flexible tube with an attached video camera into a patient's throat in order to see the patient's esophagus, stomach and small intestine lining. Endoscopic ultrasounds, laparoscopy, biopsies and MRIs may also be used.
Stomach cancer is diagnosed in four stages: in stage 1, the tumor is limited to the tissue; in stage 2, it has spread deeper, usually into the muscle layer or lymph nodes; in stage 3, the cancer has grown through all layers of the stomach; and in stage 4, it has metastasized or spread to other areas of the body.
Treatment & Therapy
There are a wide variety of different treatment options for stomach cancer; the treatment program is dictated by a patient's overall health and preferences, as well as the stage and type of gastric cancer they have been diagnosed with. Surgery is often used to remove early-stage tumors, lymph nodes or even the entire stomach, a procedure which is called a total gastrectomy.
Radiation therapy, which uses high-powered beams of energy such as X-rays to kill cancer cells, and chemotherapy, which uses chemicals to kill cancer cells that have spread throughout the body, are also frequently used to treat stomach cancer. Targeted drugs such as imatinib, trastuzumab, and sunitinib are gaining popularity after successful clinical trials.
A wide range of options exist for therapy and further treatment for cancer patients post-medical treatment. Patient support groups and follow-up care facilities exist all over the world, and the American Cancer Society provides a wealth of physical and online resources for survivors.
Prevention & Prophylaxis