2005 Abstracts: Thin-Layer Ablation of Intestinal Metaplasia with High-Grade Dysplasia in Esophagectomy Patients Using a Bipolar Radiofrequency Balloon Device (BARRx System)
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Thin-Layer Ablation of Intestinal Metaplasia with High-Grade Dysplasia in Esophagectomy Patients Using a Bipolar Radiofrequency Balloon Device (BARRx System)
C. Daniel Smith, Emory University, Atlanta, GA; Brian J. Dunkin, Pablo Bejarano, Jose Martinez, University of Miami School of Medicine, Miami, FL; Raman Muthusamy, Marco Patti, University of California, San Francisco, San Francisco, CA; W. Scott Melvin, Ohio State University School of Medicine, Columbus, OH
Background: To determine the optimal treatment parameters for the ablation of intestinal metaplasia (IM) containing high-grade dysplasia (HGD) using a balloon-based bipolar radiofrequency (RF) energy electrode.
Methods: Immediately prior to esophagectomy, subjects with biopsy-proven IM-HGD underwent EGD and ablation of a 3-cm long, circumferential segment of the diseased esophagus using a balloon-based bipolar RF energy electrode (BARRx, Sunnyvale, CA). Subjects were randomized to 1 of 2 energy density groups (10, 12, 14 J/cm2) and 1 of 3 application groups (2x, 3x or 4x). With the endoscope in place, the balloon electrode was positioned visually within the IM-HGD region. The balloon was inflated to 0.5 atm and RF energy delivered at 300 W according to randomized energy density setting. Following resection, multiple transverse and axial sections from each ablation zone were evaluated using H&E. The histologic endpoints were: 1) complete IM ablation (dead or absent tissue), 2) complete HGD ablation (dead or absent tissue), 3) maximum ablation depth. Outcomes were compared according to energy density group and number of applications. Results: Three subjects (of 9 total planned, age 50-70 years) with IM-HGD underwent the ablation procedure followed by total esophagectomy. Data is available for 2 patients; treated at 12 J/cm2 at 2x and 3x, respectively. Both had grossly evident ablation immediately after treatment, evidenced as uniform circumferential whitening and/or sloughing of the epithelium. There was no submucosa or muscularis propria ablation in either patient. At 12 J/cm2 (2x), 99.9% of IM and HGD was ablated. The one small focus of residual HGD (0.1% of surface area) was a deep gland within the lamina propria at the distal edge of the ablation zone. The edge of the treatment zone may have received only 1x treatment, possibly accounting for the tiny focus of residual disease. At 12 J/cm2 (3x), 100% of IM and HGD was ablated. The maximum depth of ablation was the muscularis mucosae in all sections for both patients. Conclusions: Complete ablation of IM-HGD, without causing injury to the submucosa or muscularis propria, is possible using this bipolar RF balloon device. 12 J/cm2 (2x and 3x) ablated to the muscularis mucosae, but never deeper. This study, with further enrollment, will identify the optimal energy density setting and applications (2x, 3x, 4x) for treating HGD in patients who otherwise would be subjected to PDT or surgical esophagectomy.
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