Circumferential and focal radiofrequency ablation for the treatment of Barrett's esophagus

How good is the neosquamous epithelium?

BACKGROUND/AIMS

Endoscopic radiofrequency ablation of dysplastic Barrett's esophagus (BE) combined with proton pump inhibitor therapy is commonly utilized for preventing progression of dysplastic BE to esophageal adenocarcinoma. Fundamental to the success of this and all ablative approaches is the healing of the ablated areas of BE with a stratified squamous epithelium referred to as 'neosquamous epithelium' (NSE). Although NSE appears 'normal' endoscopically, the reemergence of BE over time in the previously ablated segments raises the question of the health and integrity of NSE.

METHODS

The health of NSE was recently investigated in endoscopic biopsies in vitro in a group of patients after ablation while on proton pump inhibitors. Biopsies of NSE were compared to upper squamous epithelium (USE) from the same patients morphologically (light microscopy) and with respect to barrier function by measuring electrical resistance and fluorescein flux in mini-Ussing chambers.

RESULTS

Compared to USE, NSE exhibited dilated intercellular spaces and inflammation and defective barrier function by low electrical resistance and high fluorescein flux. Moreover, NSE exhibited downregulation of claudin-4, a highly expressed protein in squamous tight junctions.

CONCLUSION

NSE has defective barrier function in part due to downregulation of claudin-4. Since downregulation of claudin-4 increases paracellular permeability to cations, e.g. hydrogen ions, NSE is more vulnerable to attack and damage by acidic and weakly acidic refluxates--a phenomenon that may contribute in part to the reemergence of BE.

High-grade dysplasia and intramucosal adenocarcinoma in Barrett's esophagus: the role of esophagectomy in the era of endoscopic eradication therapy

PURPOSE OF REVIEW

The aim of this review is to evaluate the role of esophagectomy for high-grade dysplasia (HGD) and intramucosal adenocarcinoma (IMC) in light of recent advances in endoscopic therapy for Barrett's esophagus.

RECENT FINDINGS

Radiofrequency ablation (RFA) and endoscopic mucosal resection (EMR) are proven well tolerated and effective, at least in midterm follow-up. The application of these techniques has opened a new road for the local treatment of esophageal HGD and IMC. To safely employ these techniques, reliable and accurate staging of the esophageal neoplasm is essential. EMR has taken a central role, as it allows the pathologist to provide tumor-staging information necessary for an appropriate clinical management decision process. Unfortunately, both RFA and EMR have limitations that preclude their universal use in the treatment of early esophageal cancer. In some cases, esophagectomy still remains the best treatment option. The evolution of the minimally invasive approach to esophagectomy may improve outcomes of this major operation.

SUMMARY

A better understanding of the indications and limitations of endoscopic therapy for HGD and IMC permits a tailored approach to the management of patients with early esophageal adenocarcinoma. When indicated, the selection of a less morbid surgical technique has the potential to improve overall surgical and oncological outcomes.