The role of endoscopic ultrasound in the diagnosis and management of Barrett's esophagus

Management of cancer risk in Barrett's esophagus

The importance of Barrett's esophagus (BE) lies in its potential to give rise to esophageal adenocarcinoma (EAC), postulated to be through a series of progressive degrees of dysplasia; from intestinal metaplasia to low-grade dysplasia, high-grade dysplasia, and subsequently, to cancer. The management strategies for the detection and treatment of dysplasia and early esophageal cancer on a background of BE have changed significantly in the last few decades, with the emergence of newer and less invasive non-operative alternatives. This review aims to outline BE and its relation to EAC, the rationale and cost-effectiveness of both screening and surveillance programs, methods of diagnosing and identifying dysplasia and early cancer in Barrett's, and approaches to individualizing their endoscopic and surgical management based on best-available staging techniques.

Barrett's esophagus: where do we stand?

Barrett's esophagus (BE) is a precursor for esophageal adenocarcinoma, which has an increased incidence rate over the last few decades. Its importance stems from the poor five-year survival of esophageal adenocarcinoma and current data that suggest a survival benefit when surveillance programs are implemented. In this review, we will cover the pathophysiology and natural history of BE and the different endoscopic findings. The prevalence of BE in different geographic areas and the incidence of high-grade dysplasia and adenocarcinoma in this patient population is reviewed. Recent recommendation for screening and surveillance of BE has been covered in this review as well as the efficacy of nonconventional imaging modalities and endoscopic ablation therapies.

Current application of confocal endomicroscopy in gastrointestinal disorders

Confocal endomicroscopy (CEM) is a recent advancement in imaging technology that incorporates a confocal laser microscope into the tip of a flexible endoscope. The 1000-fold magnification and high resolution allows for real time in vivo histology or "virtual biopsies" of the gastrointestinal tract mucosa. CEM has the capability to instantaneously diagnose intra-epithelial neoplasia during endoscopy, alone or in combination with a "red-flag" technique, such as chromoendoscopy. Therefore, there is clinical utility in the surveillance or diagnosis of Barrett's esophagus, gastric intestinal metaplasia and cancer, longstanding ulcerative colitis, and colonic neoplasia. Furthermore, CEM also appears to be useful in the evaluation of coeliac disease, microscopic colitis, and in diagnosing Helicobacter pylori chronic gastritis. This review examines the current available data on the utility of this new technology in clinical gastroenterology and its potential impact in the future.

Emerging endoscopic techniques in oncology

New techniques have expanded the role of endoscopy in the diagnosis, staging, therapy, and palliation of malignancies. Three major areas of emerging technologies--endoscopic ultrasound (EUS), luminal stent technology, and photodynamic therapy (PDT)--are discussed in this article. Although EUS and PDT have been used for more than two decades, they have only recently emerged as established integral methods in the armamentarium of the gastrointestinal endoscopist.

Endoscopic treatment of high-grade dysplasia and early cancer in Barrett's oesophagus

Barrett's oesophagus is the premalignant precursor of oesophageal adenocarcinoma. Non-dysplastic metaplasia can progress to low-grade dysplasia, high-grade dysplasia, and finally to invasive cancer. Although the frequency of adenocarcinoma in patients with Barrett's oesophagus is low, surveillance is justified because the outcome of adenocarcinoma is poor. Oesophagectomy remains the standard treatment for patients with high-grade dysplasia and superficial carcinoma. However, it has been associated with substantial morbidity and mortality and some patients are judged unfit for surgery. In this review, the present status of less invasive procedures is discussed. Endotherapy preserves the integrity of the oesophagus and allows a better quality of life to patients at low risk of developing lymph-node metastases. Opposition to endoscopic treatment is based mainly on the identification of undetected foci of cancer and high-grade dysplasia in oesophagectomy samples. The current ablative techniques used are photodynamic therapy, argon plasma coagulation, laser treatment, and endoscopic mucosal resection.

Photodynamic therapy and endoscopic mucosal resection for Barrett's dysplasia and early esophageal adenocarcinoma

BACKGROUND

Endoscopic mucosal resection (EMR) and endoscopic ablation with porfimer sodium photodynamic therapy (PDT) have recently been combined to improve the accuracy of histologic staging and remove superficial carcinomas.

MATERIALS AND METHODS

All patients with Barrett's esophagus and high-grade dysplasia were evaluated with computed tomography and endosonography. Patients with nodular or irregular folds underwent EMR followed by PDT.

RESULTS

In three patients, endoscopic mucosal resection upstaged the diagnosis to mucosal adenocarcinoma (T1N0M0). PDT successfully ablated the remaining glandular mucosa. Complications were limited to transient chest discomfort and odynophagia.

CONCLUSIONS

The use of EMR resection in Barrett's high-grade dysplasia patients with mucosal irregularities resulted in histologic upstaging to mucosal adenocarcinoma, requiring higher laser light doses for PDT. PDT after EMR appears to be safe and effective for the complete elimination of Barrett's mucosal adenocarcinoma. EMR should be strongly considered for Barrett's dysplasia patients being evaluated for endoscopic ablation therapy.