Introduction

Endoscopic surveillance of Barrett's oesophagus is now routine.1 Cost effectiveness depends on the risk of oesophageal adenocarcinoma.2 The magnitude of this risk is unclear because most previously published studies were small and inconclusive.3 Except for one,4 these studies were not population based but investigated patients at one or more centres. Selection bias or the effect of common losses to follow up were not assessed.5 We investigated the risk of oesophageal malignancy in a large cohort of unselected patients with Barrett's oesophagus in Northern Ireland, where all incident cancers are routinely identified.

Participants, methods, and results

We examined the pathology reports relating to all oesophageal biopsies in Northern Ireland between January 1993 and December 1999. We included every adult identified within Northern Ireland (population 1.7 million) as having oesophageal columnar epithelium. We excluded biopsies taken at the oesophagogastric junction.

We defined Barrett's oesophagus as the …