February 27, 2020
By Dr Prasad G. Iyer, MD MSc FASGE, Professor of Medicine, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
Radiofrequency ablation for Barrett’s esophagus
- Radiofrequency ablation (RFA) is indicated in patients who have confirmed dysplasia, namely low grade dysplasia (LGD), high grade dysplasia (HGD), or intramucosal esophageal adenocarcinoma (EAC), that is confined to the mucosa. Confirmation of histology before proceeding with endoscopic eradication therapy is essential, given the frequent downgrading of histology (particularly of LGD) by academic pathologists with expertise in gastrointestinal pathology.
- Before initiating RFA in Barrett;s esophagus (BE), it is important to consider the elimination of all visible nodular lesions in the BE segment with endoscopic resection (cap-assisted endoscopic mucosal resection [EMR] or endoscopic submucosal dissection [ESD] for lesions >20mm). This is crucial as these nodular lesions may harbor invasive disease (submucosal or deeper invasive EAC) which should be managed surgically (and potentially with chemoradiation). Examination of endoscopic resection specimens leads to upstaging of pathology in as many as 40% of cases. Additionally, given the relatively superficial depth of injury with RFA (up to the lamina propria), deeper lesions may be incompletely treated and/or progress.
- Following the removal of all visible lesions with endoscopic resection, ablation of the remaining BE segment is recommended to reduce the risk of recurrent or metachronous dysplasia/neoplasia. Given the level 1 data available on the efficacy of RFA in preventing progression to HGD/EAC, RFA remains the modality of choice in ablating residual BE post endoscopic resection.
- RFA devices are available in circumferential and focal configurations (which can be over the scope or through the scope). For longer and circumferential segments, the Barrx TM 360 (Medtronic, MN, USA). Express catheter can be used. It has a balloon 4cm in length and is able to treat 4 cm with a single application. Following a spray of diluted N-acetyl cysteine (which acts as a mucolytic), facilitating optimal mucosal contact with the balloon, the treatment catheter is advanced over a wire into the esophagus. Under vision, the proximal edge of the balloon catheter is placed 1 cm proximal to the BE segment and ablation is begun. The balloon is moved down sequentially to complete ablation of the entire segment. The dose is 10 J per application and two applications are recommended at every site. Cleaning between applications is optional.
- Shorter noncircumferential segments are treated with focal devices which are available in three configurations: two over the scope, the Barrx TM 90 and Barrx TM 60 (Medtronic, MN, USA), and one through the scope, the Channel catheter. The device is placed in close contact with the BE mucosa and a preset energy dose (12 or 15J) is delivered (three applications sequentially if no cleaning, or two–clean–two applications if cleaning between applications). The Barrx TM catheter is useful in those in whom intubation may be somewhat challenging or in those with minimal residual disease.
- During ablation treatment, maximal reflux control is recommended to ensure optimal response with squamous re-epithelialization. This may require proton pump inhibitor (PPI) therapy twice a day in addition to bedtime H2 receptor antagonists. Ensuring compliance with this regimen is critical for ensuring an adequate response to ablation. Patients are usually seen every 3months for endoscopic treatment and surveillance. Continued diligence in inspecting the esophagus for visible lesions is important even during treatment, so that any progression (to EAC) during treatment is detected and optimally managed.
- Following successful ablation, surveillance to detect recurrences is important (rates per year: for all recurrences 9%, and for dysplastic recurrences 1%–2%). The neosquamous epithelium should be carefully inspected as should the gastroesophageal junction (GEJ). Biopsies should be taken from both of these locations and placed in separate bottles. Most recurrences tend to occur at the GEJ. They can usually be managed endoscopically with repeat endoscopic resection for visible lesions and ablation for flat recurrences. The risk of recurrence depends on preablation histology and segment length: risks are higher with HGD/mucosal EAC compared to LGD, and higher for longer BE segments.Author:
Dr. Prasad Iyer attended medical school at the All India Institute of Medical Sciences in New Delhi, India. He completed his residency at the University of Wisconsin Clinical Campus in Milwaukee, WI, and his GI Fellowship at the Mayo Clinic College of Medicine, Rochester, MN, where he also completed a postdoctoral master’s degree in clinical research. Dr. Iyer is a consultant and Professor in the Barrett’s Esophagus Unit, Division of Gastroenterology and Hepatology at the Mayo Clinic where he has been on the staff since 2006. He is a member of the Esophageal Interest and Advanced Endoscopy groups. He also directs the postdoctoral programs at the Center for Clinical and Translational Sciences at the Mayo Clinic and is Co-Director of the Advanced Esophageal Fellowship.
Dr Iyer is an Associate Editor of the journal Gastrointestinal Endoscopy and the past Chair of the International Committee of the American Society of Gastrointestinal Endoscopy (ASGE). His clinical and research interests include early detection (using minimally invasive molecular methods), risk stratification, and endoscopic therapy of Barrett’s-related neoplasia and squamous cell carcinoma of the esophagus, as well as endoscopic ultrasound. He has published over 150 peer-reviewed articles as well as several book chapters. He is a reviewer for many journals, including the New England Journal of Medicine, Gastroenterology, American Journal of Gastroenterology, Clinical Gastroenterology and Hepatology, and Gastrointestinal Endoscopy. His research program is funded by the National Cancer Institute.