Several studies have reported significant positive associations between colorectal cancer (CRC) and Barrett’s oesophagus.1-5 In the initial report, 29 colon tumours, 10 of them malignant, were found in 65 patients with Barrett’s oesophagus.1 The authors suggested that the probability of detecting a similar number of malignant colorectal lesions in an age matched sample of the general population was less than one in a million. The early studies, however, were often hampered by their choice of a “control” group or the complete absence of one. Bias may also have arisen from the discovery of Barrett’s oesophagus during the investigation of patients with gastrointestinal symptoms referable to their presentation of a CRC. In addition, the existence of asymptomatic but prevalent cases of both colon cancer and of Barrett’s oesophagus is now more widely recognised than it was a decade ago.6 Despite reservations about the validity of these studies, the finding that colon tumours seemed to be more common in patients with oesophageal intestinal metaplasia than in patients with functional bowel symptoms or with positive faecal occult blood tests is interesting on two accounts.

Firstly, the implications for a colorectal cancer screening programme of a positive association between the index cancer and Barrett’s oesophagus are considerable. The prevalence of Barrett’s oesophagus in the general population has been reported to be …