What is Stomach Cancer?

Your stomach is a J-shaped hollow organ that’s part of your upper gastrointestinal tract. The food you eat travels from your mouth, down your esophagus where it lands in the stomach to be digested, using enzymes and digestive juices to break down the food into usable nutrients. The stomach wall is made of three main layers of tissue:

  • The mucosa is the innermost layer or lining of the stomach. Most stomach cancers begin here, when cells in this inner layer erratically and abnormally change. A submucosal band of tissue serves as support for this layer.
  • The muscle layer is the middle layer where muscles contract to mix and mash your food.
  • The serosa layer is the stomach’s outer covering, which helps to hold the stomach in place. A subserosal band of tissue helps to support the serosa.


Early stomach cancer usually doesn’t cause symptoms, but as the cancer grows, some people experience:

  • Stomach discomfort or pain
  • Difficulty swallowing
  • Nausea and vomiting
  • Weight loss
  • Feeling full or bloated after a small meal
  • Vomiting blood or having blood in the stool

Other problems, such as an ulcer or infection may cause these symptoms, too, so it’s best to tell your doctor about them for prompt and accurate diagnosis.

Stomach cancer diagnosis Staging