Barrett's oesophagus and adenocarcinoma (2004)

Norman Barrett, a surgeon from St. Thomas' Hospital, first described in 1950 [1]. He described two variants of columnar-lined (Barrett's) (CLO): a congenitally with intra-thoracic gastric epithelium and congenital gastric heterotopia in the oesophagus, with ulceration. Three years later, Allison, a surgeon from Oxford, provided sound anatomical reasons why a columnar lining could occur in the as an acquired condition that appeared to be prevalent in patients with gastro-oesophageal reflux [2]. Subsequently, several authors confirmed the association of with clinical gastro-oesophageal reflux [3,4] and subsequent studies confirmed the development of following induction of gastro-oesophageal reflux in an animal model [5].

It became apparent from the histological standpoint that the columnar lined embraced a spectrum of different cellular types, principally comprising a gastric fundic type epithelium, a junctional type epithelium, which had similarities to gastric mucosa but did not secrete digestive juices, although possessing the ability to withstand acid-peptic digestion, and a distinctive type of intestinal metaplasia, characterised by the presence of goblet cells [6]. The malignant potential of the columnar lined was subsequently described [7,8], which conferred great importance on the condition and consequently on its accurate diagnosis. For this reason, and in order to eliminate any confusion between and the normal junctional columnar epithelium, as well as difficulty in identifying the precise oesophago-gastric junction in cases of hiatal hernia, an arbitrary minimal length of 3 cm of from the oesophago-gastric junction was recommended before the diagnosis of should be made [9]. Until the last few years, was defined as any histological type of columnar epithelium with a minimum length of 3 cm above the oesophago-gastric junction.

If viewed from the standpoint of the risk of developing adenocarcinoma, it became apparent that this applied only to with intestinal metaplasia (IM) and that with fundic epithelium had no malignant potential [10,11]. However, endoscopic appearances did not distinguish between the various histological types and all comprised oesophagus and were all included in the initial surveillance programmes, which resulted in a much lower incidence of adenocarcinoma than more recent series which have documented the risk in patients with intestinal metaplasia. The problem of definition has become more clouded with the realisation that segments of columnar lined with intestinal metaplasia, less than 3 cm in length, can be associated with the development of adenocarcinoma and even in short, non-circumferential tongues of columnarisation [12]. These two entities have each been referred to as short segment Barrett's since the length of these segments, which have malignant potential, fall of the 3 cm required to fulfil the definition. Subsequent studies have shown that such and usually circumferential segments of columnar lined with intestinal metaplasia are visible in 42% of adenocarcinoma of the cardia when detailed pathological examination is undertaken [13,14]. Furthermore, pathophysiological studies have shown that patients with these segments of columnarisation have gastro-oesophageal reflux disease, the pathophysiological severity of which is intermediate between that in patients with erosive oesophagitis and those with traditional CLO [15].

The problem of definition has been further compounded by numerous reports of microscopic intestinal metaplasia around the oesophago-gastric junction, present in up to 36% of patients undergoing endoscopy for a variety of gastro-intestinal symptoms, and some have referred to this phenomenon also as short-segment or ultra-short segment Barrett's [16-18]. In Spechler's series [16], only patients with traditional oesophagus and those with microscopic intestinal metaplasia at the cardia were studied, those patients with confluent or circumferential columnarisation seen endoscopically were excluded from the study. The bulk of evidence suggests that microscopic intestinal metaplasia at the cardia is not associated with gastro-oesophageal reflux disease, but associated principally with increasing age and Helicobacter infection. It is believed to have a different histogenesis from intestinal metaplasia in confluent and circumferential areas of columnarisation in the oesophagus, and its risk of malignant change appears to be extremely low [19]. In these circumstances, there is confusion in using the term short segment Barrett's interchangeably between endoscopically visible confluent or circumferential columnarisation with intestinal metaplasia and microscopic intestinal metaplasia around the cardia, and furthermore it would appear entirely inappropriate to apply the term oesophagus at all to the latter group, in the absence of endoscopically visible columnarisation, gastro-oesophageal reflux disease and a significant malignant risk.