Endoscopic therapy for high-grade dysplasia in Barrett's esophagus: ablate, resect, or both?

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

BACKGROUND AND AIMS

Endoscopic therapies for Barrett's esophagus (BE) associated dysplasia, particularly radiofrequency ablation (RFA), are popular alternatives to surgery. The effect of such therapies on dysplastic stem/progenitor cells (SPC) is unknown. Recent studies suggest that AKT phosphorylation of β-Catenin occurs in SPCs and may be a marker of activated SPCs. We evaluate the effect of RFA in restoring AKT-mediated β-Catenin signaling in regenerative epithelium.

METHODS

Biopsies were taken from squamous, non-dysplastic BE, dysplastic BE and esophageal adenocarcinoma (EAC). Also, post-RFA, biopsies of endoscopically normal appearing neosquamous epithelium were taken at 3, 6, and 12 months after successful RFA. Immunohistochemistry and Western blot analysis was performed for Pβ-Catenin(552) (Akt-mediated phosphorylation of β-Catenin), Ki-67 and p53.

RESULTS

There was no difference in Pβ-Catenin552 in squamous, GERD, small bowel and non-dysplastic BE. There was a fivefold increase in Pβ-Catenin(552) in dysplasia and EAC compared to non-dysplastic BE (P < 0.05). Also, there was a persistent threefold increase in Pβ-Catenin(552) in neosquamous epithelium 3 months after RFA compared to native squamous epithelium (P < 0.05) that correlated with increased Ki-67. Six months after RFA, Pβ-Catenin(552) and Ki-67 are similar to native squamous epithelium.

CONCLUSIONS

Enhanced AKT-mediated β-Catenin activation is seen in BE-associated carcinogenesis. Three months after RFA, squamous epithelial growth from SPC populations exhibited increased levels of Pβ-Catenin(552). This epithelial response becomes quiescent at 6 months after RFA. These data suggest that elevated Pβ-Catenin(552) after RFA denotes a repair response in the neosquamous epithelium 3 months post-RFA.

When to consider endoscopic ablation therapy for Barrett's esophagus

PURPOSE OF REVIEW

To evaluate timing and patient selection for endoscopic ablative therapy in Barrett's esophagus.

RECENT FINDINGS

There has been an explosion in the literature describing ablative therapy in Barrett's esophagus. Most recent data describe radiofrequency ablation (RFA), but other data pertain to photodynamic therapy (PDT) and other modalities. Most studies are cohort or case series. Reversion to squamous epithelium is the most common primary outcome. Cancer incidence data are scarce. RFA appears well tolerated. The main side-effect is chest pain, which can be managed with oral analgesics. Stricture occurs in 0-8% and is amenable to endoscopic dilatation. Infrequent side-effects include bleeding and perforation. Complete reversion to squamous epithelium occurs in more than 90% of nondysplastic and low-grade dysplasia and more than 80% in high-grade dysplasia patients, and the treatment appears durable for at least 2-5 years of available follow-up. Treatment of low-grade or nondysplastic disease may be cost-effective. PDT data suggest that all-cause mortality is similar to surgery for dysplastic Barrett's esophagus. The stricture rate appears higher, and rates of complete reversion to neosquamous epithelium are lower than that of RFA, although definitive comparisons are lacking.

SUMMARY

The excellent efficacy, side-effect profile, and cost-effectiveness appear to make RFA the intervention of choice in cases of high-grade dysplasia. RFA for low-grade dysplasia may be of value in young patients and/or those with long segment or multifocal disease. Treatment of nondysplastic Barrett's esophagus is of uncertain value. PDT appears to have a higher stricture rate and to be more expensive than RFA.

Barrett's Esophagus and esophageal adenocarcinoma

The incidence of esophageal adenocarcinoma (EAC) has risen dramatically over the past three decades in western countries. The importance of Barrett's esophagus (BE) derives from its potential to transform to adenocarcinoma. BE is characterized by endoscopically recognized displacement of the squamocolumnar junction proximal to the gastroesophageal junction, with replacement of squamous mucosa with columnar lined mucosa. Adenocarcinomas of the esophagus appear to arise from Barrett's mucosa through progressive degrees of dysplasia, but the pathogenesis and natural history of this process are still unclear. Much of our knowledge regarding BE and the risk of EAC is based on observational and cross-sectional analyses, and recommendations regarding management have traditionally represented "expert opinion." The past few years have seen an explosion in new information and the initiation of longitudinal studies to define the risk of adenocarcinoma in BE, the identification of predictive and prognostic markers of cancer risk, sensitive and cost-effective methods of surveillance, and methods of management of dysplasia and early neoplasia including disease prevention.

[Gastro-esophageal reflux through gastric antisecretory drugs]

During the 20th century, gastro-esophageal reflux moved from the status of a rare and severe disease to that of a frequent disease occurring mostly, in the absence of any significant lesions. Proton pump inhibitors (PPIs) are the mainstay of its therapy and are prescribed mainly in an empirical way. Extradigestive manifestations require more accurate diagnostic tests and therapeutic management. The modalities of prescription of the PPIs quickly progressed toward the on-demand therapy and over-the-counter PPIs should become widespread. The relative failures of PPIs led to a profusion of new antisecretory agents but clinical improvements are presently disappointing and the rationale of this escalation is questionable. The concept of non acid gastro-esophageal reflux opens more innovative diagnostic and therapeutic perspectives which, however, must be validated. In this respect, endoscopic treatment needs more reliable techniques and more rigorous trials. Gastro-esophageal reflux refractory to PPIs corresponds mainly to functional esophageal disorders that need diagnostic and therapeutic improvements. Barrett's esophagus constitutes a major challenge for the next few years. Its screening and its prevention seem, for the moment, inaccessible. Its survey and the prevention of its complications should benefit from progress of diagnostic and interventional endoscopy.

Minimally invasive esophagectomy for malignant and premalignant diseases of the esophagus

Minimally invasive approaches increasingly are used to treat esophageal cancer and Barrett's esophagitis with high-grade dysplasia. The goals of a minimally invasive esophageal resection are to provide sound oncologic therapy while minimizing morbidity. This article describes the technique the authors use for laparoscopic-thoracoscopic esophagectomy. Comparison data are presented for alternative endoscopic therapy primarily used in candidates not suitable for surgery.