Stomach cancer forms in tissues that line the stomach; it’s also called gastric cancer.
Most stomach cancers--90 to 95 percent--are classified as adenocarcinomas (cancers that develop from cells that line the walls of many different organs of the body). Other types of stomach cancer include squamous cell carcinoma, lymphoma, and stromal tumors (cancer of the muscle or connecting tissue). A rare gastrointestinal cancer, carcinoid tumors, develops when malignant cells are found in certain hormone-making cells of the digestive (gastrointestinal) system, or in the inner lining of this system.
Stomach cancer is difficult to discover in its early stages because the symptoms are often similar to benign conditions, such as indigestion or a viral infection of the stomach. Currently, only 10 to 20 percent of stomach cancers in the United States are found in the early stages. When any of the following symptoms persist longer than would be expected, a physician should be consulted (especially when someone is more than 50 years old):
- Unintended weight loss and lack of appetite
- Stomach pain
- Bloated feeling after eating
- Swelling of the abdomen
- Diarrhea, or constipation
- Blood in vomit or stool
Currently, there are no screening recommendations for stomach cancer; however, when a doctor suspects a patient has stomach cancer, he or she will order a series of tests that may include:
- Barium X-ray An x-ray of the stomach is taken after a liquid contrast drink is swallowed. The liquid contrast allows the stomach to be better visualized by the physician.
- Gastroscopy or Endoscopy A thin tube is inserted in the mouth and guided into the stomach. A camera at the end of the tube allows the physician to view the lining of the stomach, esophagus, and part of the small intestine. Small tissue samples can be removed for examination.
- Endoscopic Ultrasound Like a gastroscopy, a thin tube is inserted into the back of the throat. An ultrasound probe at the end of the tube releases sound waves that bounce off the stomach wall. A picture is formed on a screen from the sound waves. The test helps determine how far the cancer may have spread.
- Laparoscopy A small tube with a camera at the end is inserted into the abdomen (a minor surgical procedure) so the physician can see if cancer has spread outside the stomach.
- Computed Tomography (CT) Scan A special combination x-ray machine and computer produces cross-sectional images. This test helps determine if the cancer has spread to the liver and lymph nodes.
- Magnetic Resonance Imaging (MRI) Like a CT, an MRI also displays a cross-section of the body, but uses magnetic fields instead of radiation.
- Chest X-ray This exam is used to determine if the cancer has spread to the lungs.
- Other Tests The physician will take the patient's medical history, perform a physical examination, and order laboratory exams, such as a blood test or a fecal blood test to look for blood in the stools.
Stomach cancer was once one of the leading causes of cancer deaths in the United States, but not any more. Doctors and researchers are not sure why, but suggest the decline could be attributed to less intake of salted and smoked foods which are more likely to contain cancer-causing nitrates. Also, there has been a rise in antibiotics to treat infection: heliobacter pylori bacteria, a possible major cause of the disease, can be killed with antibiotics.
Besides excessive intake of salt and smoked foods, other risk factors include:
- Alcohol abuse
- Previous stomach surgery (such as the removal of stomach tissue due to an ulcer)
- Blood type A: for unknown reasons, people with this blood type are at higher risk
- Age: people older than 50 are more likely to develop the disease; it occurs most often in people in their 60s and 70s
- Family history of stomach cancer
- Stomach polyps
- Menetrier's disease: associated with low production of stomach acids
- Environment: stomach cancer is higher in Japan, Korea, parts of Eastern Europe, and Latin America, in parts of the world where many foods are preserved by smoking, salting, or pickling, rather than by refrigeration
- Rare conditions, such as Lynch syndrome or familial adenomatous polyposis