Post-ablation surveillance in Barrett's esophagus: A review of the literature

Barrett's Esophagus: An Updated Review

Barrett’s esophagus (BE) is a change in the distal esophageal mucosal lining, whereby metaplastic columnar epithelium replaces squamous epithelium of the esophagus. This change represents a pre-malignant mucosal transformation which has a known association with the development of esophageal adenocarcinoma. Gastroesophageal reflux disease is a risk factor for BE, other risk factors include patients who are Caucasian, age > 50 years, central obesity, tobacco use, history of peptic stricture and erosive gastritis. Screening for BE remains selective based on risk factors, a screening program in the general population is not routinely recommended. Diagnosis of BE is established with a combination of endoscopic recognition, targeted biopsies, and histologic confirmation of columnar metaplasia. We aim to provide a comprehensive review of the epidemiology, pathogenesis, screening and advanced techniques of detecting and eradicating Barrett’s esophagus.

Surveillance of neo-squamous epithelium after ablation of Barrett's esophagus: is it better to use jumbo over standard biopsy forceps?

BACKGROUND AND AIMS

As obtaining adequate tissue on biopsy is critical for the detection of residual and recurrent intestinal metaplasia/dysplasia in Barrett's esophagus (BE) patients undergone Barrett's endoscopic eradication therapy (BET), we decided to compare the adequacy of biopsy specimens using jumbo versus standard biopsy forceps.

METHODS

This is a two-center study of patients' post-radiofrequency ablation of dysplastic BE. After BET, jumbo (Boston Scientific©, Radial Jaw 4, opening diameter 2.8 mm) or standard (Boston Scientific©, Radial Jaw 4, opening diameter 2.2 mm) biopsy forceps were utilized to obtain surveillance biopsies from the neo-squamous epithelium. Presence of lamina propria and proportion of squamous epithelium with partial or full thickness lamina propria was recorded by two experienced gastrointestinal pathologists who were blinded. Squamous epithelial biopsies that contained at least two-thirds of lamina propria were considered 'adequate'.

RESULTS

In a total of 211 biopsies from 55 BE patients, 145 biopsies (29 patients, 18 males, mean age 61 years, interquartile range [IQR] 33-83) were obtained using jumbo forceps and 66 biopsies (26 patients, all males, mean age 65 years, IQR 56-76) using standard forceps biopsies. Comparing jumbo versus standard forceps, the proportion of specimens with any subepithelial lamina propria was 51.7% versus 53%, P = 0.860 and the presence of adequate subepithelial lamina propria was 17.9% versus 9.1%, P = 0.096 respectively.

CONCLUSIONS

Use of jumbo forceps does not appear to have added advantage over standard forceps to obtain adequate biopsy specimens from the neo-squamous mucosa post-ablation.

Volumetric laser endomicroscopy and its application to Barrett's esophagus: results from a 1,000 patient registry

Volumetric laser endomicroscopy (VLE) uses optical coherence tomography (OCT) for real-time, microscopic cross-sectional imaging. A US-based multi-center registry was constructed to prospectively collect data on patients undergoing upper endoscopy during which a VLE scan was performed. The objective of this registry was to determine usage patterns of VLE in clinical practice and to estimate quantitative and qualitative performance metrics as they are applied to Barrett's esophagus (BE) management. All procedures utilized the NvisionVLE Imaging System (NinePoint Medical, Bedford, MA) which was used by investigators to identify the tissue types present, along with focal areas of concern. Following the VLE procedure, investigators were asked to answer six key questions regarding how VLE impacted each case. Statistical analyses including neoplasia diagnostic yield improvement using VLE was performed. One thousand patients were enrolled across 18 US trial sites from August 2014 through April 2016. In patients with previously diagnosed or suspected BE (894/1000), investigators used VLE and identified areas of concern not seen on white light endoscopy (WLE) in 59% of the procedures. VLE imaging also guided tissue acquisition and treatment in 71% and 54% of procedures, respectively. VLE as an adjunct modality improved the neoplasia diagnostic yield by 55% beyond the standard of care practice. In patients with no prior history of therapy, and without visual findings from other technologies, VLE-guided tissue acquisition increased neoplasia detection over random biopsies by 700%. Registry investigators reported that VLE improved the BE management process when used as an adjunct tissue acquisition and treatment guidance tool. The ability of VLE to image large segments of the esophagus with microscopic cross-sectional detail may provide additional benefits including higher yield biopsies and more efficient tissue acquisition. Clinicaltrials.gov NCT02215291.

Quantifying optical properties with visible and near-infrared optical coherence tomography to visualize esophageal microwave ablation zones

Microwave ablation is a minimally invasive image guided thermal therapy for cancer that can be adapted to endoscope use in the gastrointestinal (GI) tract. Microwave ablation in the GI tract requires precise control over the ablation zone that could be guided by high resolution imaging with quantitative contrast. Optical coherence tomography (OCT) provides ideal imaging resolution and allows for the quantification of tissue scattering properties to characterize ablated tissue. Visible and near-infrared OCT image analysis demonstrated increased scattering coefficients (μ_s ) in ablated versus normal tissues (Vis: 347.8%, NIR: 415.0%) and shows the potential for both wavelength ranges to provide quantitative contrast. These data suggest OCT could provide quantitative image guidance and valuable information about antenna performance in vivo.

Care of the Postablation Patient: Surveillance, Acid Suppression, and Treatment of Recurrence

Endoscopic eradication therapy is effective and durable for the treatment of Barrett's esophagus (BE), with low rates of recurrence of dysplasia but significant rates of recurrence of intestinal metaplasia. Identified risk factors for recurrence include age and length of BE before treatment and may also include presence of a large hiatal hernia, higher grade of dysplasia before treatment, and history of smoking. Current guidelines for surveillance following ablation are limited, with recommendations based on low-quality evidence and expert opinion. New modalities including optical coherence tomography and wide-area tissue sampling with computer-assisted analysis show promise as adjunctive surveillance modalities.

Evaluation of NinePoint Medical's Nvision VLE device for gastrointestinal applications

INTRODUCTION

The incidence of esophageal adenocarcinoma (EAC) has increased over the last few decades. With a known precursor lesion, Barrett's esophagus, this remains a target for screening and surveillance with the goal of detecting and providing curative treatment for early neoplasia. Areas covered: Current surveillance techniques rely on white light endoscopy and random tissue sampling which is time consuming, costly and prone to sampling error. Volumetric laser endomicroscopy (VLE), a second-generation optical coherence technology, has emerged as an advanced imaging modality with the potential to improve dysplasia detection, surveillance and subsequently prevent esophageal adenocarcinoma. This review will focus on the use of VLE for advanced imaging of Barrett's esophagus and summarize its current and potential uses elsewhere in the GI tract. Expert commentary: NinePoint's VLE imaging device enables imaging of large segments of BE facilitating identification of luminal and subsurface abnormalities that may have otherwise been missed. Its diagnostic accuracy is improving and laser-marking system adds the capacity for accurate VLE-histologic correlation. With the adoption of dysplasia scoring systems that utilize very few VLE imaging features, inexperienced endoscopists will likely be able to pick out areas concerning for dysplasia to target therapy.