system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
In classic Barret's, the length of columnar epithelium in distal oesophagus is
assistant
The correct answer is  Classic Barrett's (>= 3cm columnar epithelium);Sho-segment Barrett's (<3 cm of columnar epithelium);Cardia metaplasia (intestinal metaplasia at the oesophagogastric junction without any macroscopic change at endoscopy).The relative risk of cancer rises with increasing length of abnormal mucosa.