The oesophagus (gullet) is the muscular tube that carries food from the mouth to the stomach (see diagram below). In Barrett's oesophagus, there are changes in the cells on the inner lining of the oesophagus, at the lower end. Barrett’s oesophagus can affect men and women, although it is more common in men.
The cell changes in Barrett’s oesophagus can sometimes develop into something called dysplasia (also called precancerous). Dysplasia can be either low-grade or high-grade. In low-grade dysplasia, the cells are slightly abnormal. In high-grade, the cells are more abnormal.
Barrett's oesophagus is not itself a cancerous condition. However, over a period of time it can occasionally lead to cancer of the oesophagus.
Cancer develops when cells in the affected area continue to grow and reproduce, and become increasingly abnormal. Approximately 1–2 out of every 200 people in the UK have Barrett's oesophagus. However, very few people with this condition go on to develop cancer. About 1–5 in every 100 people who have Barrett's oesophagus later develop cancer.