Radiofrequency ablation for dysplasia in Barrett's esophagus restores β-catenin activation within esophageal progenitor cells

The impact of flexible endoscopy in esophageal surgery

Achalasia and Treatment of esophageal Adenocarcinoma are commonly associated to surgical resection. Newer technologies in interventional endoscopy gave way to a substantial paradigm shift in the management of these conditions. In the case of achalasia, endoscopic myotomy is rapidly displacing Heller's myotomy as the gold standard in many centers. Early stage neoplasia in Barrett's esophagus (BE) comprising high-grade dysplasia (HGD), intramucosal and, in some cases, submucosal carcinoma is now being treated without the need of esophagectomy. This review presents a summary of the most relevant endoscopic techniques for both achalasia and esophageal cancer. Endoscopic advances in diagnostic and therapeutic arenas allow for minimally invasive therapies and organ preservation in most settings of achalasia and early stage neoplasia of the esophagus provided that the clinical setting and physician's expertise are prepared for this approach.

Changes in gene expression of neo-squamous mucosa after endoscopic treatment for dysplastic Barrett's esophagus and intramucosal adenocarcinoma

BACKGROUND

Endoscopic therapy, including by radiofrequency ablation (RFA) or endoscopic mucosal resection (EMR), is first line treatment for Barrett's esophagus (BE) with high-grade dysplasia (HGD) or intramucosal cancer (IMC) and may be appropriate for some patients with low-grade dysplasia (LGD).

OBJECTIVE

The purpose of this study was to investigate the molecular effects of endotherapy.

METHODS

mRNA expression of 16 genes significantly associated with different BE stages was measured in paired pre-treatment BE tissues and post-treatment neo-squamous biopsies from 36 patients treated by RFA (19 patients, 3 IMC, 4 HGD, 12 LGD) or EMR (17 patients, 4 IMC, 13 HGD). EMR was performed prior to RFA in eight patients. Normal squamous esophageal tissues were from 20 control individuals.

RESULTS

Endoscopic therapy resulted in significant change towards the normal squamous expression profile for all genes. The neo-squamous expression profile was significantly different to the normal control profile for 11 of 16 genes.

CONCLUSION

Endotherapy results in marked changes in mRNA expression, with replacement of the disordered BE dysplasia or IMC profile with a more "normal" profile. The neo-squamous mucosa was significantly different to the normal control squamous mucosa for most genes. The significance of this finding is uncertain but it may support continued endoscopic surveillance after successful endotherapy.

Management of early-stage esophageal neoplasia (MESEN) consensus

BACKGROUND

Treatment of esophageal adenocarcinoma often involves surgical resection. Newer technologies in interventional endoscopy have led to a substantial paradigm shift in the management of early-stage neoplasia in Barrett's esophagus comprising high-grade dysplasia (HGD), intramucosal carcinoma, and, in some cases, submucosal carcinoma. However, there has been no consensus regarding the indications for esophageal preservation in these cases. In this work, consensus guidelines were established for the management of early-stage esophageal neoplasia considering clinically relevant aspects (age, comorbidities, and social environment) in each scenario.

METHODS

Seventeen experts were invited to participate based on their background and clinical expertise at high-volume centers. A questionnaire was created that included four clinical scenarios covering a wide range of situations within HGD and/or early esophageal neoplasia, particularly where controversies are likely to exist. Each of the clinical scenarios was open to discussion subdivided by patient age (20, 50, and 80 s). For each clinical scenario an expert was chosen to defend that position. Each defense triggered a subsequent discussion during a consensus meeting. Conclusions of that discussion together with an accompanying literature analysis allowed experts to confirm or change their original choices and served as the basis for the recommendations stated in this article.

RESULTS

There was 100 % consensus supporting esophageal preservation in patients with HGD, independent of patient age or Barrett's length. In patients with T1a adenocarcinoma, consensus for preservation was not reached (65 %) for young and middle-aged individuals but was supported for elderly patients (100 %). For T1b adenocarcinoma, consensus was reached for surgical resection (90 %), leaving organ preservation for patients with very low risk of nodal invasion or poor surgical candidates.

CONCLUSION

Advances in endoscopic imaging and therapy allow for organ preservation in most settings of early-stage neoplasia of the esophagus, provided that the patient understands the implications of this decision.

Subsquamous intestinal metaplasia after ablation of Barrett's esophagus: frequency and importance

PURPOSE OF REVIEW

This article reviews reports on the prevalence of subsquamous intestinal metaplasia (SSIM) in patients with Barrett's esophagus, and the implications of SSIM in the neoplastic progression of Barrett's esophagus to esophageal adenocarcinoma.

RECENT FINDINGS

Endoscopic eradication therapy for dysplastic Barrett's esophagus has become an encouraging alternative to esophagectomy or continued endoscopic surveillance. However, the presence of SSIM before and after ablation is concerning because this tissue may have potential for malignant progression, is not visible by conventional endoscopy, and may evade detection by random esophageal biopsy sampling methods. Advances in endoscopic high-resolution three-dimensional optical coherence tomography recently have revealed SSIM in a majority of patients both before and after complete eradication of Barrett's esophagus by radiofrequency ablation. Studies suggest that although cells of Barrett's glands are highly proliferative, the cells of these buried glands are more dormant. Nevertheless, the malignant potential of SSIM cells remains undetermined.

SUMMARY

Novel endoscopic imaging demonstrates that SSIM is present in the majority of patients with Barrett's esophagus, both before and after ablative therapy. Although these subsquamous cells exhibit less proliferative activity than those of typical surface Barrett's glands, the malignant potential of the buried glands, especially when challenged by injurious factors, remains largely unknown. Future methods to detect subsurface dysplasia will be needed.

Molecular biomarkers and ablative therapies for Barrett's esophagus

Barrett's esophagus is the major risk factor for esophageal adenocarcinoma. Endoscopic interventions that ablate Barrett's esophagus mucosa lead to replacement with a new squamous (neosquamous) mucosa, but it can be difficult to achieve complete ablation. Knowing whether cancer is less likely to develop in neosquamous mucosa or residual Barrett's esophagus after ablation is critical for determining the efficacy of treatment. This issue can be informed by assessing biomarkers that are associated with an increased risk of progression to adenocarcinoma. Although there are few postablation biomarker studies, evidence suggests that neosquamous mucosa may have a reduced risk of adenocarcinoma in patients who have been treated for dysplasia or cancer, but some patients who do not have complete eradication of nondysplastic Barrett's esophagus may still be at risk. Biomarkers could be used to optimize endoscopic surveillance strategies following ablation, but this needs to be assessed by clinical studies and economic modeling.