Barrett’s esophagus and new therapeutic modalities

Abstract

Barrett’s esophagus is a metaplastic change of the epithelium of the esophagus, caused by injury and inflammation related to gastroesophageal reflux disease. Metaplasia is defined as the transformation from one cell type to another cell type. In the case of Barrett’s esophagus, the normal squamous epithelium is replaced by a columnar epithelium-containing goblet cells, deemed intestinal metaplasia (IM). Owing to a significantly elevated risk for the development of esophageal adenocarcinoma associated with the presence of IM, patients with this diagnosis undergo surveillance endoscopy with multiple biopsies of the diseased tissue every 2–3 years, in order to detect adenocarcinoma at the earliest possible tumor stage. Development of dysplastic cellular changes within the Barrett’s epithelium often precedes the development of cancer. In cases of IM containing dysplasia, surveillance endoscopy is performed more frequently (every 3–12 months). For many patients with high-grade dysplasia, the esophagus may be removed surgically in order to preempt the development of cancer. Removal of the Barrett’s epithelium, prior to the development of cancer, is possible. Until recently, therapy of Barrett’s esophagus was limited to those patients with the most severe form of dysplasia (high grade), and those therapies consisted of endoscopic mucosal resection, photodynamic therapy and surgical esophagectomy. However, each intervention, has been associated with specific risks to the patient. More recently, clinical data have become available regarding circumferential and focal ablation for completely removing the Barrett’s epithelium. Such ablation is performed with the HALO ablation system, which is an endoscopic catheter system that applies ablative energy to the Barrett’s epithelium in a controlled manner. Outcomes from clinical trials demonstrate that ablation with this device is safe and effective. In this review, we will briefly explore the key issues related to Barrett’s esophagus, including pathophysiology, histological grading, current management, natural history, morbidity associated with progression of the disease and methods historically used for removing the Barrett’s epithelium. We will then summarize the key issues related to newer treatment options for Barrett’s ablation, with a focused review of circumferential and focal ablation, for treating Barrett’s esophagus, including the technical components of the devices, the endoscopic technique for ablation, preclinical study, results human clinical trial results, and the role this intervention may have for the management of patients having a diagnosis of Barrett’s esophagus. Barrett’s esophagus Definition