Types of Oesophageal Cancer
There are two types of oesophageal cancer: adenocarcinoma and squamous cell carcinoma.
Adenocarcinoma is the more common type of cancer, making up 80% of all oesophageal cancers. It typically affects the lower two thirds of the oesophagus. It is associated with obesity and gastro-oesophageal reflux disease (resulting in Barrett's oesophagus), where acid escapes the stomach and enters the lower oesophagus, bathing it in stomach acid (Van Baalen, 2009).
Over time, this causes damage to the normal, healthy squamous cells in the oesophageal lining. The squamous cells are replaced with glandular cells (similar to the cells found in the stomach). This condition of Barrett's oesophagus carries with it the risk of developing oesophageal cancer.
Regular screening is necessary for those that have Barrett's oesophagus to detect any pre-cancerous cells that may develop. The incidence of adenocarcinoma is increasing rapidly, especially in western countries due to the modern diet and obesity.
Squamous cell carcinoma represents 20% of oesophageal cancers in the Western world. This figure is the opposite in Asia. It usually affects the top third of the oesophagus. They are called this because the cells lining the top part of the oesophagus are squamous cells. Squamous means scaly.
The main risk factors for squamous cell carcinoma includes smoking and excessive alcohol consumption, causing the squamous cells to become cancerous.
It is thought that, as squamous cell carcinoma is more common in the East, diet may play a factor in the risk of this type of oesophageal cancer, whereas the Western diet may be a factor in increasing the risk of adenocarcinoma.