Studies in the last several years have consistently shown radiofrequency ablation (RFA) to be effective, safe, and well tolerated in the treatment of nondysplastic and dysplastic Barrett’s esophagus (BE). The results found at academic medical centers have been reproduced in the community setting. RFA provides a safe and cost-effective alternative to surgery or surveillance in the management of high-grade dysplasia (HGD). RFA should be given serious consideration as first-line therapy for HGD. This article reviews the evidence behind RFA to differentiate it from other management strategies in terms of efficacy, durability, safety, tolerability, and cost-effectiveness. The role of RFA in the management of BE is described, including endoscopic resection. Future directions are identified for research that will help to better define the role of RFA in the management of BE.
Despite the presence of Barrett’s esophagus (BE) in 1% to 2% of the US population, its association with progression to esophageal adenocarcinoma, and a 500% increase in the incidence of esophageal adenocarcinoma (EAC) since the 1970s, the optimal management strategy for BE has not been clearly defined. When BE does progress, it seems to do so through a series of morphologic changes, from low-grade dysplasia (LGD), to high-grade dysplasia (HGD), and on to cancer. Given the 5-year survival rate of 13% for esophageal adenocarcinoma, 3 treatment strategies have been used for patients with BE and HGD: esophagectomy, intensive endoscopic surveillance, and mucosal eradication. Although usually curative, esophagectomy is associated with 3% to 5% mortality, 40% to 50% morbidity, and permanent loss of esophageal function. Meanwhile, intensive endoscopic surveillance is time and resource intensive, and still has a risk of disease progression to EAC as high as 19% at 1 year and 50% at 3 years.
Given the shortcomings of the competing strategies, mucosal ablation is appealing as a potential treatment strategy for dysplastic BE. Among the multiple endoscopic ablative strategies that have been studied in recent years, radiofrequency ablation (RFA) has shown promise because 2 prospective, multicenter clinical trials have shown it to be effective, safe, and well-tolerated. Further data are accumulating to determine whether RFA is durable and cost-effective.
This article reviews the evidence behind RFA to differentiate it from other management strategies in terms of efficacy, durability, safety, tolerability, and cost-effectiveness. The role of RFA in the management of BE is described, including endoscopic resection. Future directions are identified for research that will help to better define the role of RFA in the management of BE.
What is radiofrequency ablation?
Principles of RFA
In RFA, an alternating electrical current induces an electromagnetic field causing charged ions to rapidly oscillate, collide with one another, and create molecular friction that results in a rapid, exothermic release of thermal energy. Applied directly to esophageal tissue, it allows controlled thermal injury leading to water vaporization, coagulation of proteins, and cell necrosis. One significant advantage of RFA compared with other ablative modalities is that desiccated tissue has a much higher resistance to current than normal tissue. Thus, the coagulated lipids and proteins act as an insulator such that the system delivers an ablation depth that is consistent and well-controlled, dependent on the energy output of the probe and the frequency of the current. Seamless contact between the esophagus and the ablation interface is necessary for effective mucosal eradication to occur, and the device provides a superficial depth of injury. Therefore, RFA should generally not be applied to nodular tissue with curative intent.
Device and Procedural Technique
The only commercially available RFA system (BÂRRX Medical, Inc, Sunnyvale, CA, USA) consists of 2 partner devices, the HALO 360 device and HALO 90 device, which perform circumferential and focal ablation, respectively. The HALO 360 system consists of a sizing balloon, a balloon-based ablation catheter, and an energy generator. The ablation catheter contains a microelectrode array encircling a balloon that is capable of delivering radiofrequency energy. The array consists of 60 tightly spaced bipolar electrodes circumferentially surrounding the balloon and covering a total length of 3-cm of the balloon. The energy generator provides automated, pressure-regulated air inflation of the sizing balloon and ablation catheters. During ablation, it rapidly delivers a preset density of radiofrequency energy, measured in joules per cm 2 , to the catheter electrode.
To perform circumferential ablation, an upper endoscopy is first performed, and the length of BE is measured ( Fig. 1 A). Next, a sizing balloon is used to measure the inner diameter of the esophagus with a pressure/volume algorithm. The ablation catheter is selected such that the outer diameter of the balloon approximates the measured inner diameter of the esophagus, and then introduced over a guidewire, followed by the endoscope above it. Using endoscopic guidance, the proximal-most electrode is positioned 1 cm above the proximal edge of the BE and, by a single depression of a foot pedal, the device is activated to inflate the balloon and deliver the prespecified energy. After the first ablation, the endoscopist deflates the balloon and advances the catheter distally such that the proximal-most electrode is now aligned with the distal ablation zone, with minimal overlap (see Fig. 1 B). Ablation is again performed, and this sequence is continued until the ablation zone extends to the top of the gastric folds. At this point, the endoscope and the ablation balloon are removed from the patient. Coagulative debris are removed from the surface of the balloon using a damp 4×4-cm gauze. A soft plastic cap is affixed to the endoscope, and the patient is reintubated with the endoscope. Using the end of the cap, and with copious lavage, the treated area is debrided to remove all coagulative debris and prepare the area for a second treatment. Based on phase 2 studies using the RFA device and examining efficacy, a second treatment is then performed in similar fashion through the entire ablation zone.
The HALO 90 system consists of a device that fits on the tip of the gastroscope and is connected to the HALO 360 energy generator. The upper surface of the device has an articulated platform measuring 20-mm long by 13-mm wide with an electrode array, arranged in a similar fashion to the circumferential device. During focal ablation, the electrode is positioned on the target tissue, and then the endoscope tip is deflected up, bringing the electrode into contact with the esophageal tissue ( Fig. 2 A). Energy is delivered twice to this area (see Fig. 2 B). Afterward, the rounded, distal-most edge of the ablation catheter is used to clean coagulum from the ablation zone. The endoscope and attached device are then removed from the esophagus and cleaned. After cleaning, the endoscope and device are reinserted into the esophagus and energy again applied to the target area an additional 2 times, bringing the total number of applications to 4 per targeted area in the esophagus (see Fig. 2 C).
Ablation procedures may be performed in the outpatient setting using conscious sedation. The median time to complete the procedure is roughly 30 minutes for a circumferential procedure and 20 minutes for a focal procedure. Barring unforeseen complications, patients return home the same day and do not require inpatient admission. Oral analgesics are usually given to be used as needed for periprocedural discomfort.
Efficacy, durability, and cost-effectiveness of RFA
In High-grade Dysplastic BE
As shown in Table 1 , there have been 9 published studies to date that have analyzed the efficacy of RFA for HGD. Among 237 patients with HGD followed for a mean of 13.3 months, complete remission of intestinal metaplasia (CRIM) was noted in 67%, whereas complete remission of dysplasia (CRD) was noted in 84%.
| First Author | Year | All Patients Studied | HGD Subgroup | LGD Subgroup | NDBE Subgroup | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. Patients | Ave. Follow-up (mo) | CRIM (%) | CRD (%) | No. Patients | CRIM (%) | CRD (%) | No. Patients | CRIM (%) | CRD (%) | No. Patients | CRIM (%) | ||
| 338 | 9 | 72 | 89 | 31 | 55 | 83 | 42 | 71 | 95 | 265 | 75 | ||
| Lyday et al | 2010 | 137 | 20 | 77 | 100 | 10 | 80 | 100 | 13 | 85 | 100 | 114 | 76 |
| Vassiliou et al | 2010 | 14 | 20 | 79 | NA | 10 | 80 | NA | 2 | 100 | 100 | 1 | 100 |
| Pouw et al | 2010 | 24 | 22 | 88 | 95 | 10 | NA | NA | 11 | NA | NA | 3 | NA |
| Sharma et al | 2009 | 63 | 21 | 79 | 89 | 24 | 67 | 79 | 39 | 79 | 89 | 0 | NA |
| Velanovich | 2009 | 66 | 12 | 93 | NA | 7 | 100 | 100 | NA | NA | NA | NA | NA |
| Shaheen et al | 2009 | 84 | 12 | 77 | 86 | 42 | 74 | 81 | 42 | 81 | 90 | 0 | NA |
| Eldaif et al | 2009 | 27 | 2 | 100 | 100 | 0 | NA | NA | 2 | 100 | 100 | 25 | 100 |
| Ganz et al | 2008 | 92 | 12 | 54 | 80 | 92 | 54 | 80 | 0 | NA | NA | 0 | NA |
| Gondrie et al | 2008 | 11 | 14 | 100 | 100 | 9 | 100 | 100 | 2 | 100 | 100 | 0 | NA |
| Fleischer et al | 2008 | 62 | 30 | 97 | NA | 0 | NA | NA | 0 | NA | NA | 62 | 97 |
| Hernandez et al | 2008 | 10 | 12 | 70 | NA | 1 | 100 | 100 | 2 | 100 | 100 | 7 | 57 |
| Sharma et al | 2008 | 10 | 24 | 90 | 100 | 0 | NA | NA | 10 | 90 | 100 | 0 | NA |
| Gondrie et al | 2008 | 12 | 14 | 100 | 100 | 11 | 100 | 100 | 1 | 100 | 100 | 0 | NA |
| Sharma et al | 2007 | 100 | 12 | 67 | NA | 0 | NA | NA | 0 | NA | NA | 100 | 67 |
| Roorda et al | 2007 | 13 | 12 | 46 | 71 | 3 | NA | NA | 4 | NA | NA | 6 | NA |
| Aggregate data | 1063 | 14 | 76 | 90 | 237 | 67 | 84 | 155 | 80 | 93 | 574 | 77 | |
Related posts:
Barrett’s Esophagus: Clinical Issues
Barrett’s Esophagus Surveillance: When, How Often, Does It Work?
Biology of Barrett’s Esophagus and Esophageal Adenocarcinoma
Cryotherapy for Barrett’s Esophagus: Who, How, and Why?
Endotherapy for Barrett’s Esophagus: Which, How, When, and Who?
Role of Minimally Invasive Surgery in the Modern Treatment of Barrett’s Esophagus
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