Barrett's Oesophagus

Barrett's oesophagus, also known as Allison-Johnstone anomaly or columnar epithelium lined lower oesophagus (CELLO), is a premalignant condition affecting the oesophagus.

It involves an abnormal metaplastic change in the mucosal cells lining the lower oesophagus, transitioning from stratified squamous epithelium to simple columnar epithelium with interspersed goblet cells that are typically found only in the intestine.

This condition is significant due to its potential progression to esophageal adenocarcinoma, a notably lethal cancer.

Signs and Symptoms

Barrett's oesophagus itself does not cause specific symptoms, but it is associated with chronic acid reflux (GERD), which may present with:

• Frequent and longstanding heartburn
• Difficulty swallowing (dysphagia)
• Vomiting blood (hematemesis)
• Pain under the sternum at the oesophagus-stomach junction
• Pain when swallowing (odynophagia), potentially leading to unintentional weight loss

Obesity, particularly central obesity, increases the risk of developing Barrett's oesophagus, although the exact mechanism remains unclear.

Pathophysiology

Barrett's oesophagus arises due to chronic inflammation, primarily from gastroesophageal reflux disease (GERD). Acidic stomach contents, along with bile and pancreatic enzymes, damage the lower oesophagus cells, leading to a metaplastic transformation favouring HOXA13-expressing stem cells with intestinal characteristics.

This cellular adaptation provides resistance to acidic damage but increases the risk of carcinoma due to overexpression of HER2/neu.

Diagnosis

Diagnosis involves both endoscopic and histological examination. Endoscopy reveals the characteristic columnar epithelium replacing the normal squamous cells in the lower oesophagus. Biopsies are examined microscopically for goblet cells, indicative of intestinal metaplasia.

Screening

Screening endoscopy is recommended for males over 60 with long-term, uncontrolled reflux symptoms. The Seattle protocol, involving biopsies every 1-2 cm from the gastroesophageal junction, is commonly used. Recently, the Cytosponge, a swallowable sponge, has been introduced for sample collection, improving diagnosis rates.

Intestinal Metaplasia

Intestinal metaplasia, marked by goblet cells, is necessary for diagnosing Barrett's oesophagus. Histochemical stains like Alcian blue help differentiate true goblet cells from mimics. Immunohistochemical markers such as CDX-2 and AGR2 also aid in diagnosis.

Management

Management varies based on the presence and severity of dysplasia. Non-dysplastic Barrett's oesophagus requires surveillance endoscopy every three years. High-grade dysplasia can be treated with endoscopic mucosal resection or radiofrequency ablation. Advanced stages may necessitate surgical resection or palliation.

Anti-reflux treatments like proton pump inhibitors can limit progression to cancer. Surgical options like Nissen fundoplication and endoscopic treatments such as photodynamic therapy show promise. NSAIDs, including low-dose aspirin, have also demonstrated potential in cancer prevention.

Prognosis

Barrett's oesophagus is a premalignant condition with a variable risk of progression to esophageal adenocarcinoma, dependent on the degree of dysplasia. Dysplasia is categorised into five tiers: non-dysplastic, indefinite, low-grade, high-grade, and carcinoma.

The progression rates to esophageal adenocarcinoma are approximately 0.6% for non-dysplastic, 13.4% for low-grade dysplasia, and 25% for high-grade dysplasia. The incidence in Caucasian men is significantly higher than in women or African American men.

---

Self-assessment MCQs (single best answer)

What type of epithelium is typically found in a normal lower oesophagus?

Which of the following is NOT a symptom commonly associated with Barrett's oesophagus?

What is the primary cause of Barrett's oesophagus?

Which histological feature is essential for diagnosing Barrett's oesophagus?

What is the recommended surveillance interval for non-dysplastic Barrett's oesophagus?

Which stain is commonly used to identify goblet cells in Barrett's oesophagus?

What are the five categories of dysplasia in Barrett's oesophagus?

Which demographic has the highest incidence of Barrett's oesophagus?

Which of the following treatments is NOT typically used for high-grade dysplasia in Barrett's oesophagus?

What is the purpose of the Seattle protocol in the context of Barrett's oesophagus?