- The stomach is a significant part of the human digestive system, which takes in and breaks down food, absorbs nutrients, and eliminates waste from the body.
- Most stomach/stomach cancers begin in cells that line the inside of the stomach wall and secrete mucus. These stomach cancers are named adenocarcinomas.
- The stomach wall consists of 5 significant layers: mucosa, submucosa, muscle, subserosa, and serosa. Cancer starts in the innermost layer and progresses outward through the layers of the stomach wall.
- Gastric cancers tend to occur slowly over many years. Before cancer develops, pre-cancerous changes often appear in the mucosa (inner lining) of the stomach.
- Early-stage gastric/stomach cancer has not progressed beyond the mucosa (first layer) of the stomach wall. The tumor is often tiny and is not in any lymph nodes.
- In locoregional or locally advanced stomach cancer, cancer has invaded the submucosa (second layer) of the stomach/gastric or beyond. Cancer might be detected in regional or nearby lymph nodes.
- Cancer can progress to distant parts of the body through the lymphatic system or blood. This is known as metastatic stomach cancer. A distant metastasis could be in the abdominal lining, liver, or distant lymph nodes.