The esophagus is the muscular tube by which the food you eat travels from your mouth to your stomach. The esophagus is about 10 inches long and is referred to as the upper digestive tract.
The wall of the esophagus is composed of four layers of tissue:
- Mucosa is the innermost lining of the esophagus. This lining is moist to help food pass to the stomach.
- Submucosa contains glands which produce mucus to keep the esophagus moist.
- Muscle layer helps push food down to the stomach.
- Serosa is the outer covering of the esophagus.
Esophageal cancers begin in the cells of inner lining, or mucosa, of the esophagus. Two main cancer types occur in the esophagus:
- Adenocarcinoma is the most common esophageal cancer type in the United States. It begins in the gland cells that produce esophageal mucus. This typically occurs when stomach acids repeatedly back up into the esophagus, as in acid reflux. The acidic juices irritate and damage the gland cells, leading them to grow out of control. Adenocarcinoma usually occurs in the lower part of the esophagus, closest to the stomach.
- Squamous cell carcinoma occurs in the flat squamous cells in the upper part of the esophagus. Although this cancer type is less common in the U.S., it is the most common esophagus cancer in the rest of the world.
Early esophageal cancer may not cause symptoms. But, as the cancer grows, some people experience:
- Choking on food
- Painful swallowing
- Pain in the chest or back
- Weight loss
- Hoarseness or cough that persists beyond two weeks
Many people with esophageal cancer experience no symptoms before diagnosis, and may remain symptom-free for years.