Molecular markers and imaging tools to identify malignant potential in Barrett's esophagus

Due to its rapidly rising incidence and high mortality, esophageal adenocarcinoma is a major public health concern, particularly in Western countries. The steps involved in the progression from its predisposing condition, gastroesophageal reflux disease, to its premalignant disorder, Barrett's esophagus, and to cancer, are incompletely understood. Current screening and surveillance methods are limited by the lack of population-wide utility, incomplete sampling of standard biopsies, and subjectivity of evaluation. Advances in endoscopic ablation have raised the hope of effective therapy for eradication of high-risk Barrett's lesions, but improvements are needed in determining when to apply this treatment and how to follow patients clinically. Researchers have evaluated numerous potential molecular biomarkers with the goal of detecting dysplasia, with varying degrees of success. The combination of biomarker panels with epidemiologic risk factors to yield clinical risk scoring systems is promising. New approaches to sample tissue may also be combined with these biomarkers for less invasive screening and sur-veillance. The development of novel endoscopic imaging tools in recent years has the potential to markedly improve detection of small foci of dysplasia in vivo. Current and future efforts will aim to determine the combination of markers and imaging modalities that will most effectively improve the rate of early detection of highrisk lesions in Barrett's esophagus.     

Barrett's esophagus and esophageal adenocarcinoma.

Barrett's esophagus is a condition in which the normal stratified squamous epithelium is replaced by a specialized metaplastic columnar epithelium. It develops as a consequence of chronic gastroesophageal reflux and predisposes to the development of esophageal adenocarcinoma. Adenocarcinoma develops in Barrett's esophagus by a multistep process in which specialized metaplasia progresses to dysplasia, then to early adenocarcinoma, and eventually to deeply invasive and metastatic disease. This neoplastic progression is associated with a process of genomic instability that generates abnormal clones of cells, some of which have aneuploid or increased G2/tetraploid DNA content. A systematic protocol of endoscopic biopsy can detect Barrett's adenocarcinomas at an early stage, when they may be curable.     

Immunohistochemical markers for Barrett's esophagus and associations to esophageal Z-line appearance

BACKGROUND: Data from previous studies on intestinal metaplasia at the gastroesophageal junction have been conflicting, which makes the diagnosis of Barrett's esophagus less obvious. This may partly be due to the lack of a reliable classification of the Z-line appearance. We previously proposed such a classification (the ZAP classification) that was shown to correlate with the prevalence of intestinal metaplasia. The use of different immunohistochemical techniques has increased in the study of intestinal metaplasia. In the present study our aim was to 1) evaluate the impact of different antibodies, namely cytokeratin (CK) 7, 13, and 20, CaCO3/73, and FBB2/29, in order to differentiate between Barrett's esophagus and cardia intestinal metaplasia, and 2) explore the staining patterns in different ZAP grades. METHODS: Thirty-nine specimens with intestinal metaplasia were compared--9 from Barrett's esophagus, 6 from cardia, and 24 from the Z-line. The Z-line specimens were evaluated with respect to ZAP grade. RESULTS: No differences were encountered regarding staining patterns for CK13 and CaCO3/73 in Barrett's esophagus and cardia. The staining pattern of CK7/20 was significantly different between Barrett's esophagus and cardia. CK7/20 showed a rising frequency of Barrett's esophagus staining pattern with rising ZAP grade. CONCLUSION: CK7/20 is a feasible marker for Barrett's esophagus. Intestinal metaplasia in different ZAP grades differs regarding expression of immunohistochemical markers.     

Barrett's esophagus: Pathogenesis,epidemiology, functional abnormalities,malignant degeneration,and surgical management

Barrett's esophagus (i.e. columnar epithelial metaplasia in the distal esophagus) is an acquired condition that in most patients results from chronic gastroesophageal reflux. It is a disorder of the white male in the Western world with a prevalence of about 1/400 population. Due to the decreased sensitivity of the columnar epithelium to symptoms, Barrett's esophagus remains undiagnosed in the majority of patients. Gastroesophageal reflux disease in patients with Barrett's esophagus has a more severe character and is more frequently associated with complications as compared with reflux patients without columnar mucosa. This appears to be due to a combination of a mechanically defective lower esophageal sphincter, inefficient esophageal clearance function, and gastric acid hypersecretion. Excessive reflux of alkaline duodenal contents may be responsible for the development of complications (i.e., stricture, ulcer, and dysplasia). Therapy of benign Barrett's esophagus is directed towards treatment of the underlying reflux disease. Barrett's esophagus is associated with a 30- to 125-fold increased risk for adenocarcinoma of the esophagus. The reasons for the dramatic rise in the incidence of esophageal adenocarcinoma, which occurred during the past years, are unknown. High grade dysplasia in a patient with columnar mucosa is an ominous sign for malignant degeneration. Whether an esophagectomy should be performed in patients with high grade dysplasia remains controversial. Complete resection of the tumor and its lymphatic drainage is the procedure of choice in all patients with a resectable carcinoma who are fit for surgery. In patients with tumors located in the distal esophagus, this can be achieved by a transhiatal en-bloc esophagectomy and proximal gastrectomy. Early adenocarcinoma can be cured by this approach. The value of multimodality therapy in patients with advanced tumors needs to be shown in randomized prospective trials.     

Barrett's esophagus: Macroscopic markers and the prediction of dysplasia and adenocarcinoma

BACKGROUND AND AIMS: Surveillance endoscopy has been advocated for patients with Barrett's esophagus but the cost-effectiveness of this has been questioned. The aim of this study is to identify an optimum surveillance protocol by examining if macroscopic markers at diagnosis predict the development of dysplasia. METHODS: The sample was 353 patients with Barrett's esophagus undergoing surveillance by a community-based group of gastroenterologists between 1981 and 2001. At diagnosis the presence of macroscopic and microscopic markers was noted. The presence and pattern of dysplasia and development of adenocarcinoma was documented during subsequent surveillance. RESULTS: Three hundred and fifty-three patients (71% male) underwent regular surveillance over 19 056 patient-months (median 42 months), having a median number of three surveillance endoscopies (range 1-40). Nine patients (seven male) developed adenocarcinoma (1/176 patient years) and four male patients developed high-grade dysplasia (1/397 patient years). Twelve of these 13 patients entered with one or more macroscopic markers: severe esophagitis, nodularity, Barrett's ulcer or stricture. Dysplasia risk was associated with macroscopic markers. Patients who entered with one marker were 6.7 times more likely to develop high-grade dysplasia/adenocarcinoma (HR = 6.7, 95% CI = 1.3, 35). Patients who entered with two or more markers were 14 times more likely to develop high-grade dysplasia/adenocarcinoma (HR = 14.1, 95% CI = 2.02, 102). CONCLUSIONS: The presence of severe esophagitis, Barrett's ulcer, nodularity or stricture at entry indicates a high-risk group for Barrett's esophagus. Cost-effectiveness of surveillance for these patients and those with dysplasia at entry would thus improve.     

Barrett's esophagus. Characterization and monitoring policy

The authors review the literature about the assessment of risks of adenocarcinoma occurring over the natural history of Barrett's oesophagus with an incidence much higher than in the general population. The best marker is histological analysis of the cylindric epithelium for signs of dysplasia or early carcinoma. Although there is much controversy about the practical benefit of regular surveillance, the authors recommend a yearly endoscopy with multiple site biopsies. With the new potent drugs aimed at controlling gastro-oesophageal reflux, regression of metaplasia might occur, as the authors have observed in 3 patients treated by 60 mg omeprazole. However, prospective studies are needed to confirm this finding and its possible effect on reducing the risk of adenocarcinoma.     

Barrett's esophagus. Natural history, incidence, etiology, and complications.

This article reviews the natural history of Barrett's esophagus. The pathology and etiopathogenesis are considered in detail, as are the symptoms and complications of this condition. The indication and efficacy of medical and surgical therapy are reviewed, and the question "Does regression of Barrett's metaplasia occur?" is posed.     

Barrett's esophagus and achalasia

Two unusual cases of achalasia with endoscopic and histologic documentation of Barrett's esophagus are presented. One patient had Barrett's esophagus at the time of initial endoscopy for achalasia, before any treatment. The other patient developed specialized columnar epithelia in the esophagus after treatment with pneumatic dilation. Each patient had evidence of low-grade dysplasia. Including these two patients, 30 cases of Barrett's esophagus in patients with achalasia have been reported in the literature. In 73% (22 of 30) of the cases, Barrett's esophagus was detected after esophagomyotomy. In 20% (6 of 30) of the cases of achalasia and Barrett's esophagus, adenocarcinoma developed. The current two cases are unusual because Barrett's esophagus in achalasia generally develops from gastroesophageal reflux after esophagomyotomy. No other patients have been reported to develop Barrett's esophagus after pneumatic dilation alone. Patients with achalasia and Barrett's esophagus may be at a particularly high risk for developing dysplasia and adenocarcinoma.     

Barrett's esophagus. Prevalence and incidence of adenocarcinoma

Between January 1973 and January 1989, 241 patients with Barrett's esophagus were treated at the Lahey Clinic Medical Center, Burlington, Mass. Of these patients, 65 presented with adenocarcinoma in Barrett's esophagus for a prevalence rate of 27%. Of 176 patients followed up for a total of 497 patient-years, adenocarcinoma developed in five patients for an incidence of one per 99 patient-years. The development of adenocarcinoma during endoscopic surveillance 1, 2, 2, 4, and 10 years after the initial diagnosis of Barrett's esophagus emphasizes the importance of long-term endoscopic and histologic surveillance. All five patients had severe dysplasia before adenocarcinoma developed. Yearly endoscopic follow-up examination is recommended for all patients with Barrett's esophagus unless mild dysplastic changes are found, in which case surveillance should be increased. Patients with severe dysplasia who are otherwise acceptable candidates for operation should be advised to have esophageal resection.     

Biomarkers of Barrett's esophagus

Barrett's esophagus is the strongest risk for esophageal adenocarcinoma(EAC). Metaplasia in patients with BE may progress to dysplasia and then invasive carcinoma. Well-defined diagnostic, progressive, predictive, and prognostic biomarkers are needed to identify the presence of the disease, estimate the risk of malignant transformation, and predict the therapeutic outcome and survival of EAC patients. There are many predictive and prognostic markers that lack substantial validation, and do not allow stratification of patients with gastroesophageal reflux disease in clinical practice for outcome and effectiveness of therapy. In this short review we summarize the current knowledge regarding possible biomarkers, focusing on the pathophysiologic mechanisms to improve prognostic and therapeutic approaches.     

Barrett's esophagus: update on screening, surveillance, and treatment.

The last 2 decades have seen dramatic advances in Barrett's esophagus. The definition has evolved; the rising incidence of adenocarcinoma has been recognized; and effective therapy to control gastroesophageal reflux disease has been developed. Both proton pump inhibitor therapy and laparoscopic fundoplication represent major developments. Studies of patients with dysplasia have helped to clarify appropriate surveillance intervals and treatment strategies for these patients, although controversy still exists. The possibility of reversing Barrett's esophagus in selected high-risk patients offers major hope for the future prevention of adenocarcinoma of the esophagus.     

Barrett's esophagus and achalasia. A case report.

A 70-year-old woman with no previous gastroesophageal surgery gave a 6-month history of dysphagia. Barium studies suggested a diagnosis of achalasia. Esophageal manometry showed absence of peristalsis and a high lower esophageal sphincter pressure. Endoscopy showed a dilated esophagus with food residue, and Barrett's esophagus was present. The association of Barrett's esophagus and achalasia must be rare.     

Chemoprevention and Barrett's esophagus: decisions, decisions

The incidence of esophageal adenocarcinoma continues to increase at a rate greater than that of any other cancer in the western world. Current strategies to deal with this situation are problematic, and the time has come for new approaches to this problem. Chemoprevention is one such approach. In this issue of the American Journal of Gastroenterology, Hur et al. examined Barrett's esophagus patient preferences for cancer chemoprevention with either aspirin or celecoxib. They found that 93% of their patients were willing to take one of these two drugs, but that nearly five times as many patients preferred aspirin to celecoxib (76%vs 15%). The most important reason for willingness to use celecoxib or aspirin was cancer prevention, while the most important reason for not using celecoxib was risk of myocardial infarction and for aspirin gastrointestinal adverse events. While this study indicates that there is a strong interest among Barrett's esophagus patients for chemoprevention, it is still premature for our patients to embark on such an approach. The role of chemoprevention in Barrett's esophagus still awaits the results of ongoing clinical trials in the United Kingdom and North America.