Barrett's oesophagus
Barrett's oesophagus is the clinical entity in which the normal squamous epithelium of the lower part of the oesophagus is replaced by cylindrical metaplastic epithelium. It is an adaptive response of the oesophagus as a consequence of chronic acid reflux which destroys the normal squamous epithelium of the oesophagus and causes its replacement by cylindrical epithelium, which is more resistant to the effect of gastric acid.
Barrett's oesophagus does not cause symptoms but the importance of its existence and the associated dysplasia is that it is a pre-cancerous condition, which predisposes to the development of oesophageal adenocarcinoma. In fact, it is estimated that patients with Barrett's oesophagus are 20 times more likely than the general population to develop oesophageal adenocarcinoma.
Since Barrett's oesophagus is one of the main causes of oesophageal adenocarcinoma, the identification of patients with Barrett's oesophagus and their endoscopic surveillance play an important role in its early detection, in order to enable the early diagnosis and treatment of oesophageal cancer.
Diagnosis
In order to establish the diagnosis of Barrett's esophagus, a combination of endoscopic imaging and histological confirmation of the metaplastic epithelium is necessary.
Depending on the length of the cylindrical epithelium, Barrett's oesophagus is divided into long Barrett's (>3cm) and short Barrett's (<3cm). The length of Barrett's oesophagus also seems to be associated with the likelihood of developing oesophageal adenocarcinoma. However, histological confirmation of the presence of metaplastic epithelium is also necessary and in particular the detection of specific intestinal metaplasia since it is intestinal metaplasia that predisposes to carcinogenesis.
Epidemiology
The incidence of Barrett's esophagus in the general population is between 1.6% and 6.8%. Detection of Barrett's oesophagus is usually performed during endoscopy of patients with gastroesophageal reflux disease. Among adult patients with symptoms of gastroesophageal reflux disease, long Barrett's esophagus is detected in 3-5% of patients while short Barrett's is detected in 10-20% of patients.The risk in all patients with Barrett's disease of developing esophageal adenocarcinoma is estimated to be approximately 0.3% per year.
Risk factors
Risk factors for Barrett's esophagus and therefore esophageal cancer are considered to be advanced age, male gender, white race, obesity and chronic gastroesophageal reflux disease.
A proposed strategy to reduce the risk of death from esophageal cancer is to perform endoscopy to screen patients with gastroesophageal reflux disease (GERD) for Barrett's esophagus. However, opinions are divided as to the indication for this examination based on symptomatology alone, as it has been observed that in at least half of the cases of patients with esophageal adenocarcinoma, no history of reflux was reported. What is certain, however, is that patients with daily GERD have an increased risk of developing Barrett's esophagus compared to the rest of the population.
It has been suggested that screening should focus on patients with GERD who have risk factors for Barrett's esophagus, such as male gender, white race, age >50 years, and a long history of symptoms, and a family history of esophageal cancer.
A protective role against Barrett's oesophagus appears to be played by Helicobacter pylori infection, the use of NSAIDs and the consumption of red wine, fruit and vegetables.
Diagnostic methods
Due to the very close correlation between Barrett's esophagus and the development of adenocarcinoma, it is recommended according to the current guidelines that close endoscopic surveillance of patients with Barrett's esophagus is recommended, in order to ensure the early diagnosis of esophageal adenocarcinoma and the possibility of early intervention, especially in patients where dysplasia is detected.
Technique of endoscopic surveillance
Modern endoscopic surveillance is based on high-resolution and high-definition white light endoscopes.
Careful examination with a white light endoscope remains the basis of Barrett's esophagus surveillance.
The guidelines recommend taking biopsies from each quadrant at 2cm intervals along the Barrett's segment after the inflammation associated with GERD is controlled with antisecretory therapy.
During endoscopy, biopsies should be taken from any macroscopically obvious mucosal lesion, and biopsies should be taken systematically from the 4 quadrants every 2 cm throughout the lesion, a practice that has been shown to increase the likelihood of successful diagnosis of any degree of dysplasia. Taking biopsies of any visible lesion (ulcers, nodules, stricture, etc.) is essential as their presence is associated with an increased likelihood of detecting advanced dysplasia and/or oesophageal cancer. The rationale for such an intensive biopsy protocol follows from observations showing that high-grade dysplasia and early cancer in Barrett's esophagus often occur despite the absence of abnormalities on endoscopy.
Depending on the endoscopic and histological findings, the time of endoscopic surveillance of patients with Barrett's esophagus is determined. Patients with a short Barrett's oesophagus are at lower risk than those with a long Barrett's oesophagus, while the detection of even low-grade dysplasia is associated with an increased risk of carcinogenesis. In patients where any grade of dysplasia is detected, biopsies should be reviewed by a specialist pathologist to confirm the diagnosis of dysplasia and determine further surveillance of the patient.
Treatment
In an attempt to control reflux symptoms and heal the mucosa of the oesophagus, medication with proton pump inhibitors (PPIs) is indicated.
The place of surgical management of patients with Barrett's esophagus is now limited. This is because of the potentially serious complications and the development of newer endoscopic methods capable of treating Barrett's oesophagus, both in early stages of low-grade or high-grade dysplasia and in early oesophageal cancer localised in the mucosa. The role of surgical management is limited to patients with cancer in Barrett's esophagus territory extending beyond the submucosa.
Endoscopy offers the possibility of a variety of treatment options. Endoscopic therapeutic techniques include: endoscopic mucosal resection (EMR) and elimination of the metaplastic epithelium using various techniques such as radiofrequency ablation (RFA), phototherapy, cryotherapy (cryoablation) and argon plasma coagulation. Of these, the most important are endoscopic removal of lesions by EMR and cauterisation of Barrett's oesophagus by RFA (radiofrequency ablation).
The main endoscopic method for the treatment of high-grade dysplasia is cauterization of Barrett's dysplastic with radiofrequency ablation (RFA) through a device that is passed through the endoscope. (Image 2).
This method has an 80% success rate in the disappearance of Barrett's dysplastic. It requires 2-3 sessions with an interval of 3 months via a device that is passed through the endoscope. The same method can be used even earlier and in patients with low-grade dysplasia with up to 90% success, but at present it is of course recommended for specific patients and usually in the context of clinical studies.
An important role in the endoscopic management of Barrett's oesophagus is played by the endoscopic removal of visible lesions by the method of endomucosal resection (EMR).
Patients with visible lesions on endoscopy and either high-grade dysplasia or early esophageal cancer, which affects only the mucosa without penetrating the basement membrane (in situ carcinoma), have the greatest benefit from endoscopic mucosal resection.
It is even considered to be superior to surgical treatment both because of its clear efficacy and because of the lower mortality rate. Resection of visible lesions should be followed by cauterisation of the residual Barrett's oesophagus with radiofrequency ablation (RFA) to reduce the chance of recurrence.
It is important at this point to emphasize that endoscopic surveillance of Barrett's oesophagus with intensive biopsy continues after endoscopic treatment, at frequent intervals, to detect possible recurrence.
