Stomach cancer is an abnormal growth of cells that begins in the stomach. The stomach is a muscular sac located in the upper middle of your abdomen, just below your ribs. Your stomach receives and holds the food you eat and then helps to break down and digest it.
Stomach cancer, also known as gastric cancer, can affect any part of the stomach. In most of the world, stomach cancers form in the main part of the stomach (stomach body).
But in the United States, stomach cancer is more likely to affect the area where the long tube (esophagus) that carries food you swallow meets the stomach. This area is called the gastroesophageal junction.
Where the cancer occurs in the stomach is one factor doctors consider when determining your treatment options. Treatment usually includes surgery to remove the stomach cancer. Other treatments may be recommended before and after surgery.
Signs and symptoms of stomach cancer may include:
- Difficulty swallowing
- Feeling bloated after eating
- Feeling full after eating small amounts of food
- Stomach pain
- Unintentional weight loss
It's not clear what causes stomach cancer, though research has identified many factors that can increase the risk.
Doctors know that stomach cancer begins when a cell in the stomach develops changes in its DNA. A cell's DNA contains the instructions that tell the cell what to do. The changes tell the cell to grow quickly and to continue living when healthy cells would die. The accumulating cells form a tumor that can invade and destroy healthy tissue. With time, cells can break off and spread (metastasize) to other areas of the body.