Table 3.

Ablation therapy in Barrett’s esophagus

Ablation modalities	Description of the technique	Outcome	Ref.
RFA	RFA uses a balloon-based circumferential array of closely spaced electrodes to deliver radiofrequency energy to the esophageal mucosa. With this technique, the mucosa is ablated to the submucosal level. A smaller, endoscope-mounted, radiofrequency catheter ablation device could be used for the focal ablation of metaplasia that could remain after treatment with the circumferential system. A follow-up endoscopy is at 3 mo when any remaining metaplasia is ablated, with a further follow-up endoscopy at 1 yr	A landmark large, multicentre, randomized trial showed that RFA can eliminate HGD, reducing the risk of EAC compared with a sham procedure. Overall, the eradication rates for HGD range from 79% to 90% and from 69% and 97% for NDBE/LGD patients RFA is safer and easier to administer, and it causes fewer major complications, particularly stricture formation, than PDT	[133,145]
APC	APC produces a flow of ionized argon plasma that generates a high-frequency monopolar current to the BE surface under direct vision	Different eradication rates for NDBE and LGD in the short term ranged from 36% to 100% for NDBE and rates of recurrence between 62% and 100% for LGD patients	[133]
PDT	PDT is based on the injection of a light sensitizing drug (e.g., porfimer sodium) into the patient and then the exposure of a portion of the esophagus to light of a specific wavelength, which would lead to dysplasia cell death. Once the photosensitizer is activated by the light, it generates oxygen free radicals that result in cytotoxicity to the mucosal cells	The eradication rates for HGD range from 77% to 100%, and those for NDBE/LGD range from 50%-100% of patients The limitations include the cost of the intravenous agent, the prolonged period (weeks) of photosensitivity following exposure, and an appreciable post-treatment stricture rate	[133]
CRY	CRY is a non-contact method of cryotherapy that involves an endoscopically directed spray of liquid nitrogen at -196 °C directly onto the Barrett’s mucosa The advantage is a lack of contact with mucosa and hence can be applied to irregularity, which would make the application of contact therapies such as RFA challenging	The rates of complete eradication are approximately 68%-97% for HGD and 57% for NDBE The current literature is inadequate to assess the ability of CRY to achieve sustained reversion of the metaplastic mucosa to normal-appearing squamous epithelium in subjects at any stage of BE. Further longitudinal studies are needed	[133,156]
MPEC	MPEC uses an endoscopic multipolar electrical probe, which is used to control gastrointestinal haemorrhage that applies electrical energy at 50 W so that all BE surfaces are treated	Complete eradication in 65%-100% of NDBE. This technique is very much operator dependent and causes dysphagia as the most common side effect	[133]

RFA: Radiofrequency ablation; APC: Argon plasma coagulation; PDT: Photodynamic therapy; CRY: Cryoablation; MPEC: Multipolar electrocoagulation; EAC: Esophageal adenocarcinoma; BE: Barrett’s esophagus; IM: Intestinal metaplasia; NDBE: Non-dysplastic Barrett’s esophagus; LGD: Low-grade dysplasia; HGD: High-grade dysplasia.