Barrett's oesophagus is a term used to describe the presence of columnar epithelium in the lower oesophagus, usually as a result of metaplasia. There is ambiguity both in the historical definition and in the modern day definition of Barrett's oesophagus (see section on terminology below). For this reason some prefer the term columnar-lined oesophagus (CLO) to the eponymous label.
In essence, the normal squamous epithelium in the area is replaced by encroachment of columnar epithelium, of which there are 3 types: intestinal, gastric (fundal) and (oesphago-gastric) junctional columnar cells. Only intestinal metaplasia carries a significant risk of malignant progression. It is induced by chronic reflux.
It gives a characteristic appearance on endoscopy and diagnosis can be confirmed with biopsy. Barrett's oesophagus gives an increased risk of dysplasia and oesophageal cancer. The relative risk risk is estimated at x30-x50 and the absolute risk ~0.5% annually. However, a recent Danish study suggests the annual risk is closer to 0.12%. The literature needs to be interpreted in the context that as of 2013 there is no consensus as to the histology of the condition internationally.
The label is source of confusion as one of the two cases that Norman Barrett described in 1950 was a congenitally short oesophagus such that the gastric mucosa was pulled up into the thorax. The second was a case of congenital heterotopic gastric mucosa in the oesophagus with ulceration. The association with reflux disease was described a few years later. Indeed, Barrett's original paper supported the idea that columnar epithelium was explained by a tubular stomach being pulled up into the thorax, but his views changed in 1957. His 1957 paper, however, did not state that the columnar epithelium could be of the intestinal-type, nor did it specify the extent required to qualify for the condition he was describing.
The situation was clarified somewhat by a paper in 1976 describing the three possible types of columnar epithelium: fundal, junctional and intestinal. When to apply the label of Barrett's oesophagus remained confusing as biopsies from the oesophago-gastric junction or cardia of stomach would result in false-positive columnar epithelium, an easy mistake to make in patients with hiatus herniae or where the oesophago-gastric junction was uneven or unclear due to oesophagitis.
The diagnosis was clear enough in segments of metaplasia long enough to obviously be in the oesophagus, but for shorter segments there was no agreed cut-off. For research purposes, some investigators applied arbitrary minimum lengths, ranging from 2 to 5cm, to avoid the false-positives described. These varying length criteria were adopted by some clinicians who disregarded shorter segments of columnar epithelium. As the main concern with Barrett's oesophagus was the risk of adenocarcinoma, this had the effect of excluding shorter lesions that still carried a risk of dysplasia and malignant progression. Columnar epithelium of the fundal and junctional type were also found in resected oesophageal tumours, demonstrating non-intestinal type columnar epithelium could still represent a risk for malignancy, though some have argued that this represented intestinal-type epithelium that had lost goblet cells.
Defintitions and Diagnostic Criteria
There is general agreement that endoscopic appearences should be corroborated by histological analysis. However, the UK and American definitons differ in that histological confirmation of intestinal-type epithelium is a sine qua non. The BSG guidelines do not not insist on intestinal metaplasia on the rationale that intestinal metaplasia may be patchy and therefore prone to sampling errors. Intestinal metaplasia is thought to be present in endoscopically visible columnar-lined if sufficient biopsies are taken over time. Therefore, the combination of endoscopy and histology is important as neither is sufficient on their own; endoscopic appearences suggestive of Barrett's may harbour metaplasia of the fundal-type on histological analysis which is at low risk, while, conversely, normal-looking oesophagus may sometimes harbour microsopic intestinal metaplasia, which may be regarded as physiological.
- Cephalad displacement of the squamocolumnar junction on endoscopy
- The Z line intersection of the squamous epithelium of the tubular oesophagus and the gastric columnar epithelium is displaced either in a circumferential fashion or has tongues of columnar epithelium
- Intestinalised epithelium or epithelium containing goblet cells in a biopsy of the tubular oesophagus
The BSG 2005 guidelines recommend 4 categories for histological reporting:
- Biopsies diagnostic for columnar-lined oesophagus
- Used when native oesophageal tissue is seen adjacent to metaplastic glandular tissue.
- Biopsies corroborative of an endoscopic diagnosis of columnar-lined oesophagus
- Intestinal metaplastic glandular mucosa is seen, characterised by goblet cells, but could represent intestinal metaplasia within the cardia of the stomach or in a hiatus hernia.
- Biopsies in keeping with, but not specific for columnar-lined oesophagus
- Used when gastric-type mucosa seen, but without intestinal metaplasia. Could represent columnar-lined oesophagus, but biopsies could have come from the OG junction or stomach.
- Biopsies without evidence of columnar-lined oesophagus
- Oesophageal-type squamous mucosa with no evidence of glandular epithelium.
This is important to help determine resource effectiveness of various screening strategies. In western populations at death: about 350/100,000. Swedish prevalance is 1.6%. However the elderly may have prevalences as high as 25%, but it must be remembered the strong association with hiatus hernias and their size as well as with symptoms of GORD, although GORD does not predict Barrett's well.
Age, sex and ethnic associations exist such as white elderly men seem most at risk. Obesity is associated while chronic smoking and alcohol abuse are weakly associated. No definite protective effect of NSAIDs has been demonstrated even though there is a negative association.
Management is aimed at controlling the primary reflux, especially of gastric acid, although this often does not reverse the metaplasia. Surveillance endoscopy can detect early dysplasia. If dysplasia is severe, the traditional treatment has been prophylatic oesophagectomy, a major operation with many potential complications, including death, but this has been largely been replaced by less drastic methods of controlling dysplasia
May be associated with stricturing and therefore now losing favour.
Resolution of dysplasia in 77.4% of patients versus 2.3% in placebo in a randomised, controlled trial of a total of 127 patients.
One proprietary system of delivering this is called Halo® system.
Endoscopic Mucosal Resection
As only a small proportion of patients with Barret's oesophagus will actually develop severe dysplasia or early oesophageal cancer, it is not clear which patients will be screened and whether screening affects eventual outcome.
The British Society of Gastroenterology have produced guidelines on Barrett’s columnar-lined oesophagus .
This recommends that the most effective and cost-effective surveillance interval is two years. The guideline reports a lack of good quality evidence to support screening and this lack of evidence is highlighted in a more recent health technology assessment report . This reports that in most cases, screening does more harm than good and suggesting that it is unlikely that surveillance will be cost effective.
- ↑ Hvid-Jensen F, Pedersen L, Drewes AM, Sørensen HT, Funch-Jensen P. Incidence of adenocarcinoma among patients with Barrett's esophagus. The New England journal of medicine. 2011 Oct 13; 365(15):1375-83.(Link to article – subscription may be required.)
- ↑ a b BARRETT NR. Chronic peptic ulcer of the oesophagus and 'oesophagitis'. The British journal of surgery. 1950 Oct; 38(150):175-82.
- ↑ BARRETT NR. The lower esophagus lined by columnar epithelium. Surgery. 1957 Jun; 41(6):881-94.
- ↑ Paull A, Trier JS, Dalton MD, Camp RC, Loeb P, Goyal RK. The histologic spectrum of Barrett's esophagus. The New England journal of medicine. 1976 Aug 26; 295(9):476-80.
- ↑ Clark GW, Smyrk TC, Burdiles P, Hoeft SF, Peters JH, Kiyabu M, Hinder RA, Bremner CG, DeMeester TR. Is Barrett's metaplasia the source of adenocarcinomas of the cardia? Archives of surgery (Chicago, Ill. : 1960). 1994 Jun; 129(6):609-14.
- ↑ Cameron AJ, Lomboy CT, Pera M, Carpenter HA. Adenocarcinoma of the esophagogastric junction and Barrett's esophagus. Gastroenterology. 1995 Nov; 109(5):1541-6.
- ↑ a b c d Barrett’s columnar-lined oesophagus British Society of Gastroenterology, 2005
- ↑ a b Wang KK, Sampliner RE. Updated guidelines 2008 for the diagnosis, surveillance and therapy of Barrett's esophagus. The American journal of gastroenterology. 2008 Mar; 103(3):788-97.(Link to article – subscription may be required.)
- ↑ Trudgill NJ, Suvarna SK, Kapur KC, Riley SA. Intestinal metaplasia at the squamocolumnar junction in patients attending for diagnostic gastroscopy. Gut. 1997 Nov; 41(5):585-9.
- ↑ a b Shaheen NJ, Richter JE. Barrett's oesophagus. Lancet. 2009 Mar 7; 373(9666):850-61.(Link to article – subscription may be required.)
- ↑ Pech O, Gossner L, May A, Rabenstein T, Vieth M, Stolte M, Berres M, Ell C. Long-term results of photodynamic therapy with 5-aminolevulinic acid for superficial Barrett's cancer and high-grade intraepithelial neoplasia. Gastrointestinal endoscopy. 2005 Jul; 62(1):24-30.
- ↑ Prasad GA, Wang KK, Buttar NS, Wongkeesong LM, Krishnadath KK, Nichols FC, Lutzke LS, Borkenhagen LS. Long-term survival following endoscopic and surgical treatment of high-grade dysplasia in Barrett's esophagus. Gastroenterology. 2007 Apr; 132(4):1226-33.(Link to article – subscription may be required.)
- ↑ Shaheen NJ, Sharma P, Overholt BF, Wolfsen HC, Sampliner RE, Wang KK, Galanko JA, Bronner MP, Goldblum JR, Bennett AE, Jobe BA, Eisen GM, Fennerty MB, Hunter JG, Fleischer DE, Sharma VK, Hawes RH, Hoffman BJ, Rothstein RI, Gordon SR, Mashimo H, Chang KJ, Muthusamy VR, Edmundowicz SA, Spechler SJ, Siddiqui AA, Souza RF, Infantolino A, Falk GW, Kimmey MB, Madanick RD, Chak A, Lightdale CJ. Radiofrequency Ablation in Barrett's Esophagus with Dysplasia. The New England journal of medicine. 2009 May 28; 360(22):2277-88.(Link to article – subscription may be required.)
- ↑ Surveillance of Barrett’s oesophagus: exploring the uncertainty through systematic review, expert workshop and economic modelling Health Technology Assessment, 2006