Patients with Barrett's Oesophagus with either high grade dysplasia (HGD) or intramucosal cancer (IMC)

Collect prospective observational data on patients undergoing endoluminal therapy for dysplastic BO to determine

• Long term risk of oesophageal adenocarcinoma (OAC) development
• Long term efficacy (dysplasia and metaplasia free) in both long and short segment BO
• Short and long term safety and complications
• Comparison of the safety, long term efficacy, cost and patient tolerability between endoscopic mucosal resection (EMR) and radiofrequency ablation (RFA) Document the endoscopic location and characterise morphology of HGD/IMC in short and long segment BO Define the short term and long term causes of morbidity / mortality of patients undergoing ER This will be recorded on a datasheet, de-identified during the procedure.

Establish the effect of endoluminal therapies for BO HGD/IMC on oesophageal motility. Document and grade the post EMR oesophageal defect and establish a possible link to subsequent complications (including stricture, bleeding and perforation) and recurrence. Perform cost-utility analyses comparing different treatment approaches for BO HGD/IMC, including EMR, RFA and oesophagectomy. Establish the relationship between Obstructive Sleep Apnea and BO. Understand patient attitudes and perceptions regarding BO, its treatment and its implication.

Participants will be approached following their procedure and data recorded on a datasheet, this data will be linked to the initial procedure outcomes.