Extent of high-grade dysplasia in Barrett's esophagus correlates with risk of adenocarcinoma

Risk factors for esophageal cancer development

The incidence of esophageal adenocarcinoma is increasing at a rate greater than that of any other cancer in the Western world today. Barrett's esophagus is a clearly recognized risk factor for the development of esophageal adenocarcinoma, but the overwhelming majority of patients with Barrett's esophagus will never develop esophageal cancer. To date, dysplasia remains the only factor useful for identifying patients at increased risk for the development of esophageal adenocarcinoma in clinical practice. Other epidemiologic risk factors include aging, gender, race, obesity, reflux symptoms, smoking, and diet. Factors that may protect against the development of adenocarcinoma include infection with Helicobacter pylori, a diet rich in fruits and vegetables, and consumption of aspirin and NSAIDs.

Physical activity, obesity and risk for esophageal adenocarcinoma

Over the past three decades, an increasing incidence of esophageal adenocarcinoma (EADC) has been reported throughout North America and Europe at a rate exceeding that of any other human solid tumor. Recent studies have clearly implicated chronic gastroesophageal reflux disease and several lifestyle risk factors, including tobacco consumption, diet and obesity, to be associated with increased risk of EADC. Although physical inactivity is now recognized as a risk factor for several chronic diseases including cancer, only a very limited number of studies have specifically evaluated the association between physical activity and esophageal malignancy. Furthermore, the precise biological mechanisms underlying the association between physical activity, obesity and cancer risk remain unclear. Since successful promotion of healthy body weight and exercise may substantially reduce the future incidence of cancer in the population, the purpose of this review is to explore current evidence linking physical activity, obesity and risk of malignancy – specifically EADC.

Endoscopic therapy of Barrett's esophagus

PURPOSE OF REVIEW

Endoscopic therapy for early neoplasia arising in Barrett's esophagus has gained wide acceptance in the USA and Europe, and long-term results of endoscopic resection and photodynamic therapy and new ablation techniques are available now. This review summarizes the different indications for endoscopic treatment and the recent data on the different endoscopic treatment techniques.

RECENT FINDINGS

Endoscopic treatment of high-grade intraepithelial neoplasia has proven to be well tolerated and effective even after a long-term follow-up of more than 5 years. Radiofrequency treatment seems to be an effective technique for ablation of Barrett's esophagus with low and high-grade intraepithelial neoplasia on short-term follow-up with a very low complication rate. Recent data were able to demonstrate that biomarkers can predict the treatment effect of photodynamic therapy and several risk factors for stricture formation after treatment could be identified.

SUMMARY

Endoscopic therapy of early Barrett's neoplasia has proven to be well tolerated and effective and can be considered as the treatment of choice for most patients with this disease. Visible lesions should be treated by endoscopic resection in order to obtain a specimen for histological work up. The remaining nondysplastic Barrett's epithelium after complete resection of all neoplastic lesions should be ablated, for example, by radiofrequency treatment, to prevent metachronous or recurrent neoplasia.

Barrett esophagus: histology and pathology for the clinician

The incidence of adenocarcinoma of the esophagus and gastroesophageal junction has increased dramatically over the past 30 years. The major precursor to this type of adenocarcinoma is Barrett esophagus, which is defined as the conversion of normal squamous epithelium into metaplastic columnar epithelium. Abundant evidence suggests that adenocarcinoma in the setting of Barrett esophagus develops via a progressive sequence of histological and molecular events. Consequently, patients with Barrett esophagus routinely undergo endoscopic surveillance for early detection of neoplasia. Histological evaluation of mucosal biopsy samples from the esophagus and gastroesophageal junction for identification of goblet cells and evaluation of the presence, grade and extent of dysplasia is the mainstay of risk assessment for these patients. This Review provides physicians with a summary of the pertinent, clinically relevant histological features of Barrett esophagus and its neoplastic complications. The histology of Barrett esophagus and the gastroesophageal junction is summarized, and an overview of information necessary to interpret pathology reports from patients either with or without endoscopic evidence of Barrett esophagus is provided to appropriately guide management of patients. Close interaction between the clinician and the pathologist is essential for proper interpretation of biopsy results and to provide optimal surveillance or treatment strategies.

A histologically defined subset of high-grade dysplasia in Barrett mucosa is predictive of associated carcinoma

To ascertain the prevalence of carcinoma in esophagi resected for high-grade dysplasia (HGD) using current criteria and to evaluate histologic features that may predict concurrent carcinoma, we studied specimens from 127 esophagectomies performed for HGD, or HGD "suspicious" for carcinoma (HGD/S) in Barrett mucosa. Corresponding biopsy specimens in 69 cases were reviewed and reclassified. Based on original diagnoses, carcinoma was present in 15 (17%) of 89 HGD and 28 (74%) of 38 HGD/S cases. By reclassification, only 1 (5%) of 21 cases with HGD had carcinoma in the resection specimen. Of 25 cases reclassified as HGD/S, 18 (72%) had carcinoma in the resection specimen, as did 17 (74%) of 23 reclassified as adenocarcinoma. With 1 additional select histologic feature, the risk of carcinoma was 39%; with 2 or more features, the risk increased to 83% to 88%. Based on current criteria, no more than 5% of esophagectomies performed for a biopsy diagnosis of Barrett HGD harbor carcinoma. When HGD/S is diagnosed based on certain additional features, carcinoma is found in nearly 40% of cases with 1 feature and more than 80% with 2 or more features. Our findings highlight the evolution of diagnostic criteria for Barrett dysplasia.

Mucosal ablation of Barrett esophagus

The management of Barrett esophagus is evolving with the emergence of new endoscopic technologies. Traditionally, patients with high-grade dysplasia or cancer were referred for esophagectomy. However, with the advent of endoscopic ablative therapies for Barrett esophagus, the treatment paradigm has shifted. Patients with high-grade dysplasia and intramucosal carcinoma are increasingly offered esophagus-sparing therapies. Endoscopic ablative therapies can be categorized into tissue-acquiring and non-tissue-acquiring modalities. Visible lesions in the setting of dysplasia should be treated with a tissue-acquiring modality to stage and resect the lesion appropriately. One or more modalities may be used to eradicate the entire region of affected esophagus totally. Total eradication treats all of the at-risk epithelium and, therefore, treats any metachronous or synchronous lesions. Success of treatment may be gauged by complete remission of cancer, dysplasia, or Barrett esophagus. In addition to procedure-related complications, the risk of residual Barrett esophagus or subsquamous Barrett esophagus remains to be addressed. Endoscopic surveillance and acid suppression is still currently required after ablation.

Where are you and how do we find you? The dilemma of identifying Barrett's epithelium before adenocarcinoma of the esophagus

The incidence of esophageal adenocarcinoma in white males has been increasing steadily over the past decade. However, attempts to identify the precursor lesion, intestinal metaplasia of the esophagus, or early in-situ cancers have been dismal, with no increase in the diagnosis of early cancers over 9 years of follow-up, as noted in the study by Cooper et al. Important predictors of survival,such as a previous diagnosis of gastroesophageal reflux disease, endoscopy, and the diagnosis of intestinal metaplasia, continue to represent a minority of patients who present with esophageal adenocarcinoma. A discussion on the possible pathophysiology, and reasons for the poor diagnostic yields in spite of performing more endoscopies, are presented. It may be that most patients are relatively asymptomatic, or have very distal, endoscopically imperceptible intestinal metaplasia. Over time, factors that encourage localized, distal esophageal reflux may be the insidious culprit that leads to intestinal metaplasia.

The Society of Thoracic Surgeons practice guideline series: guidelines for the management of Barrett's esophagus with high-grade dysplasia

The management of Barrett's esophagus with high-grade dysplasia is controversial. The standard of care has traditionally been esophagectomy. However, a number of treatment options aimed at esophageal preservation are increasingly being utilized by many centers. These esophageal-sparing approaches include endoscopic surveillance, mucosal ablation, and endoscopic mucosal resection. In this guideline we review the best evidence supporting these commonly used strategies for high-grade dysplasia to better define management and guide future investigation.

The Seattle protocol does not more reliably predict the detection of cancer at the time of esophagectomy than a less intensive surveillance protocol

BACKGROUND & AIMS

The optimal management of high-grade dysplasia in Barrett's esophagus remains controversial. A biopsy protocol consisting of 4 quadrant jumbo biopsies (every 1 cm) with biopsies of mucosal abnormalities (the Seattle protocol) is considered to be the optimal method for detecting early cancers in patients with high-grade dysplasia, although it has never been validated. This study aimed to determine the frequency of unsuspected carcinoma at esophagectomy in Barrett's esophagus patients with high-grade dysplasia who underwent the Seattle protocol and to compare the findings with those of a less rigorous biopsy protocol.

METHODS

Thirty-three patients with high-grade dysplasia underwent esophagectomy. None had obvious mass lesions at preoperative endoscopy. Patients were divided into group 1 (preoperative surveillance biopsies according to Seattle protocol) and group 2 (4 quadrant biopsies every 2 cm). Preoperative and postoperative diagnoses were confirmed by 2 expert gastrointestinal pathologists.

RESULTS

Unsuspected intramucosal cancer was found in 8 of 20 (40%) patients in group 1 versus 4 of 13 (30%) in group 2 (P = .6). Preoperative mucosal nodularity was observed in 4 of 8 (50%) postoperative intramucosal cancers from group 1 versus 3 of 4 (75%) from group 2. Multifocal high-grade dysplasia was seen preoperatively in 7 of 8 (87.5%) postoperative intramucosal cancers in group 1 versus 2 of 4 (50%) in group 2. No patient had submucosal cancer or lymph node metastases at surgery.

CONCLUSIONS

Intense preoperative biopsy sampling by the Seattle protocol does not more reliably predict the detection of cancer at the time of esophagectomy than a less intensive surveillance protocol. This calls into question the concept that extensive sampling with the Seattle protocol consistently detects early cancers arising in Barrett's esophagus patients with high-grade dysplasia.

Radiofrequency ablation in Barrett's esophagus with dysplasia

BACKGROUND

Barrett's esophagus, a condition of intestinal metaplasia of the esophagus, is associated with an increased risk of esophageal adenocarcinoma. We assessed whether endoscopic radiofrequency ablation could eradicate dysplastic Barrett's esophagus and decrease the rate of neoplastic progression.

METHODS

In a multicenter, sham-controlled trial, we randomly assigned 127 patients with dysplastic Barrett's esophagus in a 2:1 ratio to receive either radiofrequency ablation (ablation group) or a sham procedure (control group). Randomization was stratified according to the grade of dysplasia and the length of Barrett's esophagus. Primary outcomes at 12 months included the complete eradication of dysplasia and intestinal metaplasia.

RESULTS

In the intention-to-treat analyses, among patients with low-grade dysplasia, complete eradication of dysplasia occurred in 90.5% of those in the ablation group, as compared with 22.7% of those in the control group (P<0.001). Among patients with high-grade dysplasia, complete eradication occurred in 81.0% of those in the ablation group, as compared with 19.0% of those in the control group (P<0.001). Overall, 77.4% of patients in the ablation group had complete eradication of intestinal metaplasia, as compared with 2.3% of those in the control group (P<0.001). Patients in the ablation group had less disease progression (3.6% vs. 16.3%, P=0.03) and fewer cancers (1.2% vs. 9.3%, P=0.045). Patients reported having more chest pain after the ablation procedure than after the sham procedure. In the ablation group, one patient had upper gastrointestinal hemorrhage, and five patients (6.0%) had esophageal stricture.

CONCLUSIONS

In patients with dysplastic Barrett's esophagus, radiofrequency ablation was associated with a high rate of complete eradication of both dysplasia and intestinal metaplasia and a reduced risk of disease progression. (ClinicalTrials.gov number, NCT00282672.)

Surgery versus radical endotherapies for early cancer and high grade dysplasia in Barrett's oesophagus

BACKGROUND

Barrett's oesophagus is one of the most common premalignant lesions in the world. Currently the mainstay of therapy is surgical management of advanced cancer but this has improved the five-year survival very little in the last 30 years. As a consequence, improved survival relies on early detection through endoscopic surveillance programmes. Success of this strategy relies on the fact that late stage premalignant lesions or very early cancers can be cured by intervention. Currently there is considerable controversy over which method is best: i.e. conventional open surgery or endotherapy (techniques involving endoscopy).

OBJECTIVES

We used data from randomised controlled trials to examine the effectiveness of endotherapies compared with surgery, in people with Barrett's Oesophagus; those with early neoplasias (defined as high grade dysplasia (HGD), and those with early cancer (defined as carcinoma in-situ, superficially invasive, early cancer or superficial cancer T-1m (T1-a) and T-1sm (T1-b)).

SEARCH STRATEGY

We used the Cochrane highly sensitive search strategy to identify randomized trials in MEDLINE, EMBASE, CENTRAL, ISI Web of Science, EBMR, Controlled Trials mRCT and ISRCTN and LILACS, in July and August 2008.

SELECTION CRITERIA

Types of studies: randomised controlled trials comparing endotherapies with surgery in the treatment of high grade dysplasia (HGD), or early cancer. All cellular types of cancer were included (i.e. adenocarcinomas, squamous cell carcinomas and more unusual types) but will be discussed separately.

TYPES OF PARTICIPANTS

patients of any age and either gender with a histologically confirmed diagnosis of early neoplasia (HGD and early cancer) in Barrett's or squamous lined oesophagus.Types of interventions; endotherapies (the intervention) compared with surgery (the control), all with curative intent.

DATA COLLECTION AND ANALYSIS

Reports of studies which meet the inclusion criteria for this review would have been analysed using the methods detailed in Appendix 9.

MAIN RESULTS

We did not identify any studies which met the inclusion criteria.

AUTHORS' CONCLUSIONS

This Cochrane review has indicated that there are no randomised control trials to compare management options in this vital area, therefore trials should be undertaken as a matter of urgency. The problems with such randomised methods are standardising surgery and endotherapies in all sites; standardising histopathology in all centres; assessing which patients are fit or unfit for surgery; and making sure there are relevant outcomes for the study i.e. no progression of high grade dysplasia or long term survival i.e. over five years.

Endocytoscopy in esophageal cancer

Endocytoscopy is a new imaging and magnification technology. It has been developed for observation of cellular structure and applied in the esophageal cancer. In this article we summarize the important aspects of this new modality.

Barrett's oesophagus

Barrett's oesophagus is a metaplastic change of the lining of the oesophagus, such that the normal squamous epithelium is replaced by specialised or intestinalised columnar epithelium. The disorder seems to be a complication of chronic gastro-oesophageal reflux disease, although asymptomatic individuals might also be affected, and it is a risk factor for the development of oesophageal adenocarcinoma, a cancer with rapidly increasing incidence in developed societies. We review the presentation, epidemiology, and risk factors for this condition. We discuss the molecular changes necessary for the development of Barrett's oesophagus and its progression to cancer, and new strides in both the endoscopic detection of the lesion and the treatment of dysplastic disease. Also, we assess the effectiveness of efforts to screen patients at risk of Barrett's oesophagus, and whether such efforts avert cancer death. We conclude with a discussion of future directions for research, focusing on treatment of early neoplasia, and modifications of current practices to show our evolving understanding of this condition.

Screening, surveillance, and prevention for esophageal cancer

The incidence of esophageal cancer, especially esophageal adenocarcinoma, is increasing and its high mortality rate is a notable fact. Improving survival rates of this disease depend on earlier detection through screening and surveillance; however, standard diagnostic modalities, such as endoscopy with biopsy, have several limitations as screening tools, including low negative predictive value and relatively high cost. Recently developed biomarkers such as FISH and improved imaging techniques, may help overcome current problems and provide improved screening and surveillance for esophageal cancer.

Frequency of the mitochondrial DNA 4977bp deletion in oesophageal mucosa during the progression of Barrett's oesophagus

PURPOSE

The mechanisms of the progression of Barrett's oesophagus (BO) to oesophageal adenocarcinoma (OA) are poorly understood. The frequency of the 4977bp deletion in mitochondrial DNA (mtDNA) was investigated in specimens ranging from normal oesophageal tissue to OA in order to investigate whether this deletion represents a useful biomarker of disease progression.

METHODS

The presence of the 4977bp deletion was screened by PCR amplification from 70 specimens in total.

RESULTS

The frequency of specimens with the 4977bp deletion increased in relation to the degree of dysplasia (8.3% in normal squamous epithelium; 15.4% in BO; 40% in low grade dysplasia (LGD); 69.2% in high-grade dysplasia and 90% in para-tumoural tissue). However, the frequency of the deletion reduced sharply in OA specimens (16.7%; p<0.001).

CONCLUSION

The mtDNA 4977bp deletion may be useful as a biomarker to detect the severity of dysplasia but not the presence of OA.

Patient predictors of histopathologic response after photodynamic therapy of Barrett's esophagus with high-grade dysplasia or intramucosal carcinoma

BACKGROUND

Photodynamic therapy (PDT) has been used extensively for endoscopic ablation of Barrett's esophagus with high-grade dysplasia (HGD) or intramucosal carcinoma.

OBJECTIVE

To identify patient variables that influence the likelihood of response to PDT.

DESIGN

A retrospective cohort study.

SETTING

Tertiary-referral center.

PATIENTS

A total of 116 patients with Barrett's esophagus and with HGD, intramucosal carcinoma, or T1 cancer.

INTERVENTIONS

PDT with porfimer sodium.

MAIN OUTCOME MEASUREMENTS

(1) Ablation of HGD and/or intramucosal carcinoma and (2) eradication of all Barrett's epithelium.

RESULTS

Of the patients, 51% underwent treatment for HGD and 49% of patients had intramucosal carcinoma or T1 cancer. At 12-month follow-up, ablation of HGD and/or cancer was observed in 70% of patients, and ablation of all Barrett's epithelium was observed in 39%. In multivariate analysis, the pretreatment length of Barrett's esophagus was inversely correlated with successful ablation of all Barrett's epithelium. Patients with Barrett's esophagus length more than 3 cm were less likely to experience complete ablation compared with patients with Barrett's esophagus length 3 cm or less (odds ratio [OR] 0.15 [95% CI, 0.04-0.50]). Patients with intramucosal carcinoma were not significantly less likely to experience elimination of HGD and/or cancer (OR 0.77 [95% CI, 0.30-2.00]) or ablation of all Barrett's epithelium (OR 0.82 [95% CI, 0.32-2.07]) compared with patients with HGD alone.

LIMITATIONS

Retrospective study, limited sample size without a control group for comparison.

CONCLUSIONS

PDT of Barrett's esophagus with HGD, intramucosal carcinoma, or T1 cancer can result in ablation of dysplasia and/or eradication of all Barrett's epithelium. Factors associated with the likelihood of response include length of Barrett's esophagus. The presence of intramucosal carcinoma or T1 cancer was not associated with higher likelihood of treatment failure.

Barrett's esophagus in 2008: an update

With the rising incidence and overall poor prognosis of esophageal adenocarcinoma (EA) there is great interest in furthering our understanding of Barrett's esophagus, the precursor lesion for most cases of EA. The best available evidence from true population-based analysis suggests that the prevalence of Barrett's is 1.6%. In addition, nearly half of the patients with Barrett's are asymptomatic. Several risk factors for development of Barrett's have been identified including gastro-esophageal reflux disease (GERD), central obesity, H. pylori eradication, and male gender. The precise incidence of progression from Barrett's to esophageal adenocarcinoma is not known, but it probably is less than 0.5% per year, and our ability to predict who is at highest risk for progression remains poor. The degree of dysplasia is currently used as a marker for risk of progression to cancer though there is increasing evidence that biomarkers and level of genetic instability may provide better predictive measures. Intensive acid-suppression and COX-2 inhibition are potential strategies to reduce the risk of progression, though definitive studies are needed. Endoscopic surveillance remains the mainstay of management for non-dysplastic and low grade dysplasia Barrett's. The advent of various endoscopic ablative therapies has provided a promising alternative to surgery for Barrett's patients with high grade dysplasia (HGD).

Barrett's esophagus

Barrett's esophagus is an important step in the pathway to esophageal adenocarcinoma. Since most patients with Barrett's esophagus are undiagnosed and patients present with advanced adenocarcinoma de novo, prognosis for this disease remains poor. To identify those people with Barrett's esophagus who are at particular risk many new technologies are being developed. In association with these advances in risk stratification, progress is being made in the endoscopic treatment of Barrett's. Chemoprevention is also an area of interest and trials are underway.

Update on the diagnosis and treatment of Barrett esophagus and related neoplastic precursor lesions

CONTEXT

At present, Barrett esophagus is the most common cause of esophageal adenocarcinoma. In the past 20 years, the incidence of esophageal adenocarcinoma in white males has exceeded that of tumors of the colorectum, lung, prostate, and skin.

OBJECTIVES

To (1) provide an evidence-based review of the diagnosis, classification, and histologic differentiation of Barrett esophagus from gastric carditis, (2) provide a summary of the key pathologic features of precursor lesions, such as dysplasia, and (3) evaluate adjunctive markers of dysplasia and predictive markers for the development of cancer. The natural history and risk of cancer in patients with Barrett esophagus is also reviewed.

DATA SOURCES

For this review, selected published peer reviewed articles were chosen from a search through PubMed between the years 1970 and 2007.

CONCLUSIONS

The current definition of Barrett esophagus is partially flawed because not all cases are endoscopically recognizable, nongoblet epithelium is biologically intestinalized, and determination of the presence or absence of goblet cells is susceptible to sampling error. Differentiation of ultrashort segment Barrett esophagus from chronic gastric carditis can be accomplished, in a minority of cases, by evaluating for the presence or absence of histologic features that are known to be associated with Barrett esophagus. Dysplasia in Barrett esophagus begins in the crypt bases and then extends more superficially to include the upper portions of the crypts and surface epithelium. Low- and high-grade dysplasia are distinguished by the presence of marked cytologic and/or architectural abnormalities in the latter compared with the former. There are few, if any, reliable adjunctive diagnostic techniques that can help differentiate nondysplastic from dysplastic epithelium. However, alpha-methylacyl coenzyme A racemase staining has been shown to be useful in 2 separate studies. Both low- and high-grade dysplasia are progressive lesions, and in general, the extent of dysplasia, particularly low grade, is a strong risk factor for progression to carcinoma. Of all the biologic and genetic biomarkers studied to date, evaluation of DNA content is the most reliable and specific. The management of patients with dysplasia is variable among institutions and ranges from aggressive surveillance, endoscopic mucosal resection, mucosal ablation, or total esophagectomy.

The hippo pathway in human upper gastrointestinal dysplasia and carcinoma: a novel oncogenic pathway

BACKGROUND

The Hippo (Hpo) pathway is highly conserved in humans and was originally uncovered in Drosophila as a potent regulator of inhibiting cell growth and promoting apoptosis. The Hippo pathway consists of a tumor suppressor kinase cascade that negatively regulates growth and results in inactivation of a transcriptional co-activator, Yorkie (yki). The human ortholog of Yki, the yes-associated protein (YAP), has a 31% sequence identity and similar biologic activity. The potential role of YAP in tumorigenesis was also reported in a murine genetic screen which identified a genomic amplification of YAP in hepatocellular carcinoma.

AIM

Given this pathway's critical control of cell growth, survival, proliferation, and amplification in malignancy, we wanted to explore the possible role of the Hippo pathway in human esophageal and gastric tumorigenesis.

METHOD

The expression of YAP was evaluated with immunolabeling of esophageal and gastric tissue microarrays from 169 patients, with nondysplastic, dysplastic, and malignant foci represented. Cytoplasmic and nuclear staining were scored as 0 = none, 1 < 10%, 2 = 10-50%, and 3 > 50% for the nonneoplastic, dysplastic, and malignant epithelium. Multiple scores were averaged for each patient. Expression of YAP could be seen in the proliferating compartments of nonneoplastic tissue.

RESULTS

Compared to nonneoplastic epithelium, there was a significant increase in YAP cytoplasmic and nuclear localization in high-grade dysplastic epithelium and adenocarcinoma of the esophagus. There was also a significant increase in YAP cytoplasmic and nuclear staining of gastric carcinoma and metastatic gastric disease compared to nonneoplastic gastric tissue.

CONCLUSIONS

YAP expression in the cytoplasm and nucleus is significantly increased in high-grade dysplasia and adenocarcinoma of the esophagus as well as gastric adenocarcinoma and metastatic gastric disease, suggesting a role for this recently uncovered pathway in esophageal and gastric epithelial tumorigenesis.

Management of high-grade dysplasia

High-grade dysplasia is the last stage before the development of adenocarcinoma. Despite the fact that the lesion is not yet invasive, it has tremendous potential to become malignant. The approach to the disease has clinicians divided between immediate intervention with surgical resection or continued endoscopic surveillance proof of the unclear natural history. Much knowledge has been acquired recently regarding application of surveillance and outcomes of esophageal resection. Also, many endoscopic techniques for treating high-grade dysplasia have been studied in depth. Results on their safety, efficacy, and complication rates have recently become available. This review analyzes the progress in the understanding and treatment of high-grade dysplasia during the past 24 to 36 months and examines how this new information plays a role in the disease's treatment algorithm.

HER-2 overexpression/amplification in Barrett's oesophagus predicts early transition from dysplasia to adenocarcinoma: a clinico-pathologic study

Barrett's oesophagus (BO) is the primary precursor lesion for oesophageal adenocarcinoma (ADC). The natural history of metaplasia-dysplasia-carcinoma sequence remains largely unknown. HER2/neu oncogene results overexpressed/amplified in preneoplastic lesions and in ADC of the oesophagus and it has been associated with poor prognosis. Our aim was to evaluate the role of HER2 overexpression/amplification in predicting the conversion from precursor lesions to ADC. We retrospectively evaluated by univariate analysis of single variables clinical records and histological specimens of 21 patients with a confirmed diagnosis of BO and/or oesophageal dysplasia. Clinical variables included age, gender, alcohol and smoking intake, presence of symptoms (pyrosis, disphagia) and endoscopic features (length). HER2 status was studied by immunohistochemistry and fluorescence in situ hybridization (FISH) on paraffin-embedded tissue. The end-points were the occurrence of progression and the time-to-progression (TTP) from the initial histologic lesion to the worst pathological pattern. Median age at diagnosis was 63 years (range 37-84). BO median length was 4.5 cm. Progression occurred in 11 of 21 patients and median TTP was 24 months. HER2 was overexpressed/amplified in 8 of 21 (38%) patients. HER2 overexpression/ amplification and the presence of dysplasia were statistically associated with progression (P= 0.038). This study provides evidence for a possible role of HER2 in the transition from dysplasia to ADC of the oesophagus. This fact could help in identifying patients at high risk of malignant transformation.

HER-2 overexpression/amplification in Barrett's oesophagus predicts early transition from dysplasia to adenocarcinoma: a clinico-pathologic study

Barrett’s oesophagus (BO) is the primary precursor lesion for oesophageal adenocarcinoma (ADC). The natural history of metaplasia-dysplasia-carcinoma sequence remains largely unknown. HER2/neu oncogene results overexpressed/amplified in preneoplastic lesions and in ADC of the oesophagus and it has been associated with poor prognosis. Our aim was to evaluate the role of HER2 overexpression/amplification in predicting the conversion from precursor lesions to ADC. We retrospectively evaluated by univariate analysis of single variables clinical records and histological specimens of 21 patients with a confirmed diagnosis of BO and/or oesophageal dysplasia. Clinical variables included age, gender, alcohol and smoking intake, presence of symptoms (pyrosis, disphagia) and endoscopic features (length). HER2 status was studied by immunohistochemistry and fluorescence in situ hybridization (FISH) on paraffin-embedded tissue. The end-points were the occurrence of progression and the time-to-progression (TTP) from the initial histologic lesion to the worst pathological pattern. Median age at diagnosis was 63 years (range 37–84). BO median length was 4.5 cm. Progression occurred in 11 of 21 patients and median TTP was 24 months. HER2 was overexpressed/amplified in 8 of 21 (38%) patients. HER2 overexpression/ amplification and the presence of dysplasia were statistically associated with progression (P= 0.038). This study provides evidence for a possible role of HER2 in the transition from dysplasia to ADC of the oesophagus. This fact could help in identifying patients at high risk of malignant transformation.

Circumferential and focal radiofrequency ablation for the treatment of Barrett's esophagus

This invited profile summarizes the technical aspects and clinical trial results related to the use of circumferential and focal radiofrequency ablation in the management algorithm for Barrett's esophagus. What makes this relatively new endoscopic intervention unique is its promising safety and efficacy profile reported in published clinical trials. This technology appears to have overcome many of the limitations of prior endoscopic ablative modalities, and is thus garnering a role in the management of this disease state.

Barrett's esophagus and the increasing role of endoluminal therapy

Barrett's esophagus, or the presence of specialized intestinal mucosa in the esophagus that has a malignant potential, has experienced a rapid increase in diagnosis and prevalence over the past few decades. Once thought to progress to adenocarcinoma in an orderly sequence of increasing dysplasia, recent data suggest the process can be more random. In combination with targeted surveillance endoscopy, recent improvements in technology have aided endoluminal therapy in becoming a cost-effective adjunct to medication. When used in combination, in particular, these ablative therapies have become suitable, if not preferable, alternatives to surgery in many patients.

Poor interobserver agreement in the distinction of high-grade dysplasia and adenocarcinoma in pretreatment Barrett's esophagus biopsies

OBJECTIVE

Grading Barrett's dysplasia at the lower end of the metaplasia-dysplasia spectrum (negative, indefinite, and low-grade dysplasia) suffers from poor interobserver agreement, even among gastrointestinal pathologists. Data evaluating interobserver agreement in Barrett's mucosal biopsies with changes at the upper end of the dysplasia spectrum (high-grade dysplasia, intramucosal, and submucosal adenocarcinoma) have not been published. The accurate categorization of pretreatment biopsies drives therapeutic decision making, but if the diagnostic distinction between cancer and high-grade dysplasia in Barrett's biopsies is inconsistent, then the use of these diagnoses to make management decisions is suspect. To this end, our aim was to assess interobserver reproducibility among a group of gastrointestinal pathologists in the interpretation of preresection biopsies.

METHODS

All study pathologists agreed upon the histologic criteria distinguishing four diagnostic categories, including high-grade dysplasia; high-grade dysplasia with marked distortion of glandular architecture, cannot exclude intramucosal adenocarcinoma; intramucosal adenocarcinoma; and submucosally invasive adenocarcinoma. The histologic criteria were used to independently review preresection biopsies from 163 consecutive Barrett's esophagus patients with at least high-grade dysplasia who ultimately underwent esophagectomy. Reviewers recorded the specific histologic criteria used to categorize each case and Kappa statistics were calculated to assess interobserver agreement.

RESULTS

Using kappa statistics, the overall agreement was only fair (kappa= 0.30). Agreement for high-grade dysplasia was moderate (kappa= 0.47), while agreement for high-grade dysplasia with marked architectural distortion, cannot exclude intramucosal adenocarcinoma and intramucosal adenocarcinoma were only fair (kappa= 0.21 and 0.30, respectively) and agreement for submucosal adenocarcinoma was poor (kappa= 0.14).

CONCLUSIONS

The overall poor interobserver reproducibility among gastrointestinal pathologists who see a high volume of Barrett's cases calls into question treatment regimens based on the assumption that high-grade dysplasia, intramucosal adenocarcinoma, and submucosal adenocarcinoma can reliably be distinguished in biopsy specimens.

Histological assessment of oesophageal columnar mucosa

This review presents the pathological features of Barrett's oesophagus, with an emphasis on the role of pathologists in the diagnosis, surveillance and treatment of the disease. The diagnosis of Barrett's oesophagus is based both on endoscopy and histology. The surveillance of patients relies on systematic biopsy sampling, looking for dysplasia - intraepithelial neoplasia. Well established classifications of dysplasia are now used by pathologists, but there remain problems with this marker. Therefore, many alternative biomarkers have been proposed, that remain of limited interest in daily practice, including DNA-ploidy, proliferation markers, and p53 abnormalities. Endoscopic improvements already allow a better selection of biopsies, and it may be that new technologies will allow 'virtual biopsies'. The role of pathologists is now extended to the evaluation of new therapeutic modalities of early neoplastic lesions in Barrett's oesophagus, especially endoscopic mucosal resection.

Utility of biomarkers in prediction of response to ablative therapy in Barrett's esophagus

BACKGROUND & AIMS

Photodynamic therapy (PDT) has been shown to be effective in the treatment of high-grade dysplasia (HGD)/mucosal carcinoma in Barrett's esophagus (BE). Substantial proportions of patients do not respond to PDT or progress to carcinoma despite PDT. The role of biomarkers in predicting response to PDT is unknown. We aimed to determine if biomarkers known to be associated with neoplasia in BE can predict loss of dysplasia in patients treated with ablative therapy for HGD/intramucosal cancer.

METHODS

Patients with BE and HGD/intramucosal cancer were studied prospectively from 2002 to 2006. Biomarkers were assessed using fluorescence in situ hybridization performed on cytology specimens, for region-specific and centromeric probes. Patients were treated with PDT using cylindric diffusing fibers (wavelength, 630 nm; energy, 200 J/cm fiber). Univariate and multiple variable logistic regression was performed to determine predictors of response to PDT.

RESULTS

A total of 126 consecutive patients (71 who underwent PDT and 55 patients who did not undergo PDT and were under surveillance, to adjust for the natural history of HGD), were included in this study. Fifty (40%) patients were responders (no dysplasia or carcinoma) at 3 months after PDT. On multiple variable analysis, P16 allelic loss (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.10-0.96) predicted decreased response to PDT. BE segment length (OR, 0.71; 95% CI, 0.59-0.85), and performance of PDT (OR, 7.17; 95% CI, 2.50-20.53) were other independent predictors of loss of dysplasia.

CONCLUSIONS

p16 loss detected by fluorescence in situ hybridization can help predict loss of dysplasia in patients with BE and HGD/mucosal cancer. Biomarkers may help in the selection of appropriate therapy for patients and improve treatment outcomes.

Should patients with Barrett's oesophagus be kept under surveillance? The case for

Oesophageal adenocarcinoma is associated with high mortality rates and its incidence is increasing more rapidly than any other gastrointestinal cancer in the Western world. Several factors, including gastro-oesophageal reflux disease, smoking, alcohol and male gender, are associated with oesophageal adenocarcinoma but none can be used to identify accurately those individuals who will develop adenocarcinoma. It is generally accepted that oesophageal adenocarcinoma arises predominantly in Barrett's oesophagus and it is arguable that Barrett's oesophagus is currently the only clinically useful predictor of oesophageal adenocarcinoma. Surveillance - periodic testing to detect adenocarcinoma or its precursor, high grade dysplasia - is widely recommended for patients with Barrett's oesophagus with the aim of reducing mortality from oesophageal adenocarcinoma. The annual incidence of oesophageal adenocarcinoma in patients with Barrett's oesophagus is 0.5%-1.0% although there is marked variation between studies, attributable variously to publication bias, concurrent acid suppression therapy and differences in patient characteristics. There is limited evidence that surveillance reduces the incidence of oesophageal adenocarcinoma or consequent mortality and the cause of death for patients undergoing surveillance is often unrelated to oesophageal disease. There are, nonetheless, observational studies which suggest that surveillance is associated with earlier detection of malignancy and a reduction in mortality; in addition, data from modelling studies suggest that surveillance can be cost-effective. Furthermore, the advent of new, non-surgical treatments (endoscopic mucosal resection, photodynamic therapy, argon plasma coagulation) for high grade dysplasia and early cancer has reduced the risks associated with therapy for disease detected during surveillance. Surveillance programs have high drop out rates and, for patients who continue surveillance, adherence to standard, published protocols is highly variable. The establishment of specialist Barrett's oesophagus surveillance programs, with coordinator support, has considerable potential to improve adherence to current guidelines, pending the acquisition and publication of data from ongoing studies of chemoprophylaxis and surveillance in the management of Barrett's oesophagus. In consequence, although there is a paucity of data providing unequivocal demonstration of benefit, there is no proof that surveillance is ineffective. It is, therefore, appropriate to offer surveillance for Barrett's oesophagus in accordance with locally-applicable published guidelines after a full informed discussion of the risks and benefits of surveillance and therapy; continued participation should be reviewed regularly to accommodate changes in the patient's health and expectations.

Endoscopic approaches to Barrett's oesophagus with high-grade dysplasia/early mucosal cancer

This chapter will review the endoscopic approaches to the management of Barrett's oesophagus with high-grade dysplasia/early mucosal cancer. Factors to consider when evaluating patients for endoscopic management are detailed. Ablation and resection methods for eradication of Barrett's oesophagus with high-grade dysplasia/early mucosal cancer are reviewed. Strategies for combining therapies to achieve safe and effective eradication are discussed. Recommendations for complete eradication of all Barrett's mucosa and follow-up considerations are put forward.

Circumferential ablation of Barrett's esophagus that contains high-grade dysplasia: a U.S. Multicenter Registry

BACKGROUND

The management strategies for Barrett's esophagus (BE) that contains high-grade dysplasia (HGD) include intensive endoscopic surveillance, photodynamic therapy, thermal ablation, EMR, and esophagectomy.

OBJECTIVE

To assess the safety and effectiveness of endoscopic circumferential balloon-based ablation by using radiofrequency energy for treating BE HGD.

DESIGN

Multicenter U.S. registry.

SETTING

Sixteen academic and community centers; treatment period from September 2004 to March 2007.

PATIENTS

Patients with histologic evidence of intestinal metaplasia (IM) that contained HGD confirmed by at least 2 expert pathologists. A prior EMR was permitted, provided that residual HGD remained in the BE region for ablation.

INTERVENTION

Endoscopic circumferential ablation with follow-up esophageal biopsies to assess the histologic response to treatment.

OUTCOMES

Histologic complete response (CR) end points: (1) all biopsy specimen fragments obtained at the last biopsy session were negative for HGD (CR-HGD), (2) all biopsy specimens were negative for any dysplasia (CR-D), and (3) all biopsy specimens were negative for IM (CR-IM).

RESULTS

A total of 142 patients (median age 66 years, interquartile range [IQR] 59-75 years) who had BE HGD (median length 6 cm, IQR 3-8 cm) underwent circumferential ablation (median 1 session, IQR 1-2). No serious adverse events were reported. There was 1 asymptomatic stricture and no buried glands. Ninety-two patients had at least 1 follow-up biopsy session (median follow-up 12 months, IQR 8-15 months). A CR-HGD was achieved in 90.2% of patients, CR-D in 80.4%, and CR-IM in 54.3%.

LIMITATIONS

A nonrandomized study design, without a control arm, a lack of centralized pathology review, ablation and biopsy technique not standardized, and a relatively short-term follow-up.

CONCLUSIONS

Endoscopic circumferential ablation is a promising modality for the treatment of BE that contains HGD. In this multicenter registry, the intervention safely achieved a CR for HGD in 90.2% of patients at a median of 12 months of follow-up.

Barrett's columnar-lined oesophagus: demographic and lifestyle associations and adenocarcinoma risk

OBJECTIVES

Lifestyle and demographic risk factors for the development of oesophageal adenocarcinoma developing from columnar-lined oesophagus are not well defined.

METHODS

Demographic and lifestyle factors, endoscopy and histology reports were extracted from 1,761 subjects from seven UK centres. The associations of columnar-lined oesophagus with demographic and lifestyle factors and the development of adenocarcinoma were examined.

RESULTS

5.5% of patients had prevalent adenocarcinoma (more common in males, older patients, patients diagnosed earlier in the cohort and current or recent smokers). Adenocarcinoma incidence was 23 patients in 3,912 years or 0.59% per annum. Only increased age at diagnosis correlated with an increased risk of incident adenocarcinoma. There was no association with obesity or alcohol history.

CONCLUSIONS

Oesophageal adenocarcinoma occurs more commonly in older patients and is more frequent in males than females. Once columnar-lined oesophagus had been diagnosed, there were no other demographic or lifestyle factors which were predictive of the development of incident adenocarcinoma in this cohort.

Incidence of esophageal adenocarcinoma in patients with Barrett's esophagus and high-grade dysplasia: a meta-analysis

BACKGROUND

Patients with Barrett's esophagus (BE) and high-grade dysplasia (HGD) are at a high risk for developing esophageal adenocarcinoma. However, the reported rate of cancer development in patients with HGD who were undergoing surveillance has varied among published studies.

OBJECTIVE

To determine an overall precise estimate of cancer incidence in patients with HGD who were undergoing surveillance endoscopy.

DESIGN

Systematic review and meta-analysis.

METHODS

We conducted a systematic search of the published literature and selected original articles that examined patients with histologically proven BE and HGD, patients who had not undergone endoscopic ablation or surgical therapy, patients with 6 months' follow-up, no esophageal cancer at the time of enrollment or within 6 months, and studies in which follow-up was reported in person-time. Two investigators independently conducted the search and abstraction.

MAIN OUTCOME MEASUREMENT

The weighted mean event rate was calculated and expressed as the weighted incidence rate, and its CIs were calculated.

RESULTS

The search yielded 4 articles that met the inclusion criteria, and these were analyzed. A total of 236 patients with HGD were followed for 1241 patient-years, and esophageal adenocarcinoma was reported in 69 patients, providing a crude incidence rate of 5.57 per 100 patient-years. The weighted incidence rate was 6.58 per 100 patient-years (95% CI, 4.97-8.19).

LIMITATIONS

A small number of studies that met inclusion criteria.

CONCLUSIONS

In patients with BE and with HGD who were undergoing surveillance, esophageal adenocarcinoma develops in approximately 6 per 100 patient-years during the first few years of follow-up. These data may better inform physicians and patients in management decisions.

Effect of proton pump inhibitors on markers of risk for high-grade dysplasia and oesophageal cancer in Barrett's oesophagus

BACKGROUND

It has been shown that the presence on diagnosis of endoscopic macroscopic markers indicates a high-risk group for Barrett's oesophagus.

AIM

To determine whether proton pump inhibitor therapy prior to diagnosis of Barrett's oesophagus influences markers for risk development of subsequent high-grade dysplasia/adenocarcinoma.

METHODS

A review of all patients with Barrett's oesophagus entering a surveillance programme was undertaken. Five hundred and two patients diagnosed with Barrett's oesophagus were assessed on diagnosis for endoscopic macroscopic markers or low-grade dysplasia. Subsequent development of high-grade dysplasia/adenocarcinoma was documented. The relationship between the initiation of proton pump inhibitor therapy prior to the diagnosis of BE and the presence of macroscopic markers or low-grade dysplasia at entry was determined.

RESULTS

Fourteen patients developed high-grade dysplasia/adenocarcinoma during surveillance. Patients who entered without prior proton pump inhibitor therapy were 3.4 times (95% CI: 1.98-5.85) more likely to have a macroscopic marker or low-grade dysplasia than those patients already on a proton pump inhibitor.

CONCLUSIONS

Use of proton pump inhibitor therapy prior to diagnosis of Barrett's oesophagus significantly reduced the presence of markers used to stratify patient risk. Widespread use of proton pump inhibitors will confound surveillance strategies for patients with Barrett's oesophagus based on entry characteristics but is justified because of the lower risk of neoplastic progression.

Is the risk of concomitant invasive esophageal cancer in high-grade dysplasia in Barrett's esophagus overestimated?

BACKGROUND & AIMS

Recent studies have claimed long neoplasia-free survival rates with endoscopic mucosal resection of high-grade dysplasia (HGD) in Barrett's esophagus (BE). However, reports have contended that approximately 40% of patients who have esophagectomy for HGD have occult invasive cancer. The aim of this study was to use explicit criteria to determine the true prevalence of invasive adenocarcinoma in reports of patients who had esophagectomy for HGD in BE.

METHODS

Studies reporting rates of esophageal cancer in patients who underwent esophagectomy for HGD in BE were gathered using MEDLINE and PUBMED. We defined invasive esophageal adenocarcinoma (IEAC) as tumor with submucosal invasion or beyond. Intramucosal carcinoma (IMC) was not considered IEAC.

RESULTS

Twenty-three articles were selected for analysis. Most investigators reported rates of invasive cancer in the esophagectomy specimen, and the pooled average was 39.9% among the 441 patients who underwent an esophagectomy for HGD. Reported rates varied from 0% to 73%. A total of 267 patients had American Joint Committee on Cancer stage 0 postoperatively, 132 patients had stage I, 23 patients had stage IIa, 10 patients had stage IIb, and 9 patients had stage III. Fourteen studies provided differentiation between intramucosal and submucosal invasion. Among 213 patients, only 12.7% had IEAC, whereas 87.3% had HGD or IMC. The IEAC rate of 11% among patients with visible lesions is greater than the rate of 3% among patients with no visible lesion.

CONCLUSIONS

By using strict pathologic definitions of invasive disease, the present study indicates the true prevalence of IEAC in BE and HGD may have been overestimated significantly. Separating IMC from IEAC is clinically relevant because endoscopic techniques potentially may treat IMC.

Management of early esophageal cancer

In early esophageal cancer, squamous cell cancer and early adenocarcinoma must be managed differently because they have different origins, pathogenesis. and clinical characteristics. The current treatment options vary widely, from extended resection with lymphadenectomy to endoscopic mucosectomy or ablation. None of these treatment options can be recommended universally. Instead, an individualized strategy should be based on the depth of tumor infiltration into the mucosa or submucosa, the presence or absence of lymph node metastases, the multicentricity of tumor growth, the length of the segment of intestinal metaplasia, and comorbidities of the patient. Endoscopic mucosectomy may be sufficient in a subset of patients who have m1 or m2 squamous cell carcinoma and in patients who have isolated foci of high-grade intraepithelial neoplasia or mucosal cancer. Surgical resection is the treatment of choice for carcinomas invading the submucosal and multicentric tumors. Limited resection with jejunal interposition provides an effective treatment option for patients who have early esophageal adenocarcinoma. The onset of lymph node involvement is later in patients who have early adenocarcinoma than in patients who have squamous cell cancer, probably because chronic injury and repair mechanisms obliterate the otherwise abundant lymph vessels.

Barrett's Esophagus: Diagnosis, Screening, Surveillance, and Controversies

Barrett's esophagus (BE) is a frequent complication of gastroesophageal reflux disease, an acquired condition resulting from persistent mucosal injury to the esophagus. The incidence of Barrett's metaplasia and Barrett's adenocarcinoma has been increasing, but the prognosis of Barrett's adenocarcinoma is worse because individuals present at a late stage. Attempts have been made to intervene at early stage using surveillance programmes, although proof of efficacy of endoscopic surveillance is lacking. There is much to be learned about BE. Whether adequate control of gastroesophageal reflux early in the disease alters the natural history of Barrett's change once it has developed remains unanswered. Thus there is great need for carefully designed large randomised controlled trials to address these issues in order to determine how best to manage patients with BE. The AspECT and BOSS clinical trials proride this basis.

Esophagectomy for high grade dysplasia is safe, curative, and results in good alimentary outcome

BACKGROUND

The increasing adoption of endoscopic therapies and expectant surveillance for patients with high grade dysplasia (HGD) in Barrett's esophagus has created considerable controversy regarding the ideal treatment choice. Confusion may be due, in part, to a limited understanding of the outcomes associated with surgical resection for HGD and extrapolation of data derived from patients undergoing an esophagectomy for invasive cancer. The purpose of our study was to document the perioperative and symptomatic outcomes and long-term survival after esophagectomy for HGD of the esophagus.

MATERIAL AND METHODS

The study population consisted of 38 patients who underwent esophagectomy for biopsy-proven HGD between 10/1999 and 6/2005. Three patients were excluded from analysis due to obvious tumor on upper endoscopy. Patients were evaluated regarding ten different foregut symptoms and administered a ten-question appraisal of eating and bowel habits. Outcome measures included postoperative morbidity and mortality, the prevalence of invasive cancer in the esophagectomy specimens, symptomatic and functional alimentary results, patient satisfaction, and long-term survival. Median follow-up was 32 months (range, 7-83).

RESULTS

Thirty-day postoperative and in-hospital mortality was zero. Complications occurred in 37% (13/35), and median length of stay was 10 days. Occult adenocarcinoma was found in 29% (10/35) of surgical specimens (intramucosal in four; submucosal in five; and intramuscular in one with a single positive lymph node.) Patients consumed a median of three meals per day, most (76%, 26/34) had no dietary restrictions, and two-thirds (23/34) considered their eating pattern to be normal or only mildly impacted. Meal size, however, was reported to be smaller in the majority (79%, 27/34) of patients. Median body mass index (BMI) decreased slightly after surgery (28.6 vs 26.6, p>0.05), but no patient's BMI went below normal. The number of bowel movements/day was unchanged or less in a majority (82%) of patients after surgery. Fifteen of 34 (44%) patients reported loose bowel movements, which occurred less often than once per week in 10 of the 15. One patient had symptoms of dumping. Mean symptom severity scores improved for all symptoms except dysphagia and choking. Four patients developed foregut symptoms that occurred daily. Most patients (82%) required at least one postoperative dilation for dysphagia. Almost all (97%) patients were satisfied. Disease-free survival was 100%, and overall survival was 97% (34/35) at a median of 32 months.

CONCLUSION

Esophagectomy is an effective and curative treatment for HGD and can be performed with no mortality, acceptable morbidity, and good alimentary outcome. These data provide a gold standard for comparison to alternative therapies.

Neoplastic precursor lesions in Barrett's esophagus

Barrett's esophagus, currently defined as endoscopically apparent columnar metaplasia of the esophagus with histologic documentation of goblet cells, is the precursor to esophageal adenocarcinoma. However, not all patients with this disorder require intensive surveillance. Pathologic diagnosis and grading of dysplasia in mucosal biopsies remains the best and most widely used method of determining which patients are at highest risk for neoplastic progression. The task of diagnosing dysplasia suffers from considerable interobserver variability. Therefore, consultation with expert gastrointestinal pathologists to confirm the diagnosis of dysplasia before definitive management is highly advisable. Adjunctive methods to improve reproducibility, such as immunostaining for alpha-methylacyl-CoA racemase, show promise but require confirmation in larger studies. This article focuses on dysplasia in Barrett's esophagus in terms of its classification, pathologic diagnostic criteria, limitations, natural history, and treatment.

Molecular changes in the progression of Barrett's oesophagus

Barrett's oesophagus is a frequent complication of gastro-oesophageal reflux disease predicting oesophageal adenocarcinoma. The majority of Barrett's patients will not develop cancer, so that specific methods of identification of those at risk are required. Recent molecular studies have identified a selection of candidate biomarkers that need validation in prospective studies. They reflect various changes in cell behaviour during neoplastic progression. The ASPECT trial in the UK aims to establish whether chemoprevention with aspirin and a proton pump inhibitor will reduce adenocarcinoma development and mortality in patients with Barrett's oesophagus. It will also validate biomarkers for progression and clinical response and further study disease pathogenesis.