Molecular evaluation of ablative therapy of Barrett's oesophagus

High Expression of Methylenetetrahydrofolate Dehydrogenase 2 (MTHFD2) in Esophageal Squamous Cell Carcinoma and its Clinical Prognostic Significance

BACKGROUND Recently, targeted therapy for malignant tumors has developed rapidly, but there is still no effective targeted therapy for advanced esophageal squamous cell carcinoma (ESCC). Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) is a key enzyme involved in folate metabolism and is closely related to the proliferation in many cancers. However, few studies have explored the expression of MTHFD2 in ESCC and its prognostic significance. MATERIAL AND METHODS The expressions of MTHFD2, ki67, and p53 in ESCC tissues were detected by immunohistochemistry. Further, MTHFD2 expression level in ESCC and its correlations with patients' clinicopathological characteristics and survival prognosis were investigated. RESULTS The enhanced expression of MTHFD2 was observed in ESCC specimens compared with adjacent normal tissue. The increased expression of MTHFD2 was closely related to pathological grading (P=0.020) and tumor TNM stage (P=0.019). In addition, patients with high expression of MTHFD2 had worse survival than those with low MTHFD2 expression (P<0.05). High expression of MTHFD2 in ESCC tissues was often associated with high expression of ki67 and p53 (P<0.05). CONCLUSIONS MTHFD2 had significantly enhanced expression in ESCC tissues and was associated with pathological grading and TNM stage. Taken together, high expression of MTHFD2 was an independent unfavorable prognostic parameter for overall survival (OS) of ESCC patients, suggesting that MTHFD2 might be a potential therapeutic target for ESCC in the future.

Screening for esophageal adenocarcinoma and precancerous conditions (dysplasia and Barrett's esophagus) in patients with chronic gastroesophageal reflux disease with or without other risk factors: two systematic reviews and one overview of reviews to inform a guideline of the Canadian Task Force on Preventive Health Care (CTFPHC)

BACKGROUND

Two reviews and an overview were produced for the Canadian Task Force on Preventive Health Care guideline on screening for esophageal adenocarcinoma in patients with chronic gastroesophageal reflux disease (GERD) without alarm symptoms. The goal was to systematically review three key questions (KQs): (1) The effectiveness of screening for these conditions; (2) How adults with chronic GERD weigh the benefits and harms of screening, and what factors contribute to their preferences and decision to undergo screening; and (3) Treatment options for Barrett's esophagus (BE), dysplasia or stage 1 EAC (overview of reviews).

METHODS

Bibliographic databases (e.g. Ovid MEDLINE®) were searched for each review in October 2018. We also searched for unpublished literature (e.g. relevant websites). The liberal accelerated approach was used for title and abstract screening. Two reviewers independently screened full-text articles. Data extraction and risk of bias assessments were completed by one reviewer and verified by another reviewer (KQ1 and 2). Quality assessments were completed by two reviewers independently in duplicate (KQ3). Disagreements were resolved through discussion. We used various risk of bias tools suitable for study design. The GRADE framework was used for rating the certainty of the evidence.

RESULTS

Ten studies evaluated the effectiveness of screening. One retrospective study reported no difference in long-term survival (approximately 6 to 12 years) between those who had a prior esophagogastroduodenoscopy and those who had not (adjusted HR 0.93, 95% confidence interval (CI) 0.58-1.50). Though there may be higher odds of a stage 1 diagnosis than a more advanced diagnosis (stage 2-4) if an EGD had been performed in the previous 5 years (OR 2.27, 95% CI 1.00-7.67). Seven studies compared different screening modalities, and showed little difference between modalities. Three studies reported on patients' unwillingness to be screened (e.g. due to anxiety, fear of gagging). Eleven systematic reviews evaluated treatment modalities, providing some evidence of early treatment effect for some outcomes.

CONCLUSIONS

Little evidence exists on the effectiveness of screening and values and preferences to screening. Many treatment modalities have been evaluated, but studies are small. Overall, there is uncertainty in understanding the effectiveness of screening and early treatments.

SYSTEMATIC REVIEW REGISTRATIONS

PROSPERO (CRD42017049993 [KQ1], CRD42017050014 [KQ2], CRD42018084825 [KQ3]).

MicroRNA profile in neosquamous esophageal mucosa following ablation of Barrett's esophagus

AIM

To investigate the microRNA expression profile in esophageal neosquamous epithelium from patients who had undergone ablation of Barrett's esophagus.

METHODS

High throughput screening using TaqMan® Array Human MicroRNA quantitative PCR was used to determine expression levels of 754 microRNAs in distal esophageal mucosa (1 cm above the gastro-esophageal junction) from 16 patients who had undergone ablation of non-dysplastic Barrett's esophagus using argon plasma coagulation vs pretreatment mucosa, post-treatment proximal normal non-treated esophageal mucosa, and esophageal mucosal biopsies from 10 controls without Barrett's esophagus. Biopsies of squamous mucosa were also taken from 5 cm above the pre-ablation squamo-columnar junction. Predicted mRNA target pathway analysis was used to investigate the functional involvement of differentially expressed microRNAs.

RESULTS

Forty-four microRNAs were differentially expressed between control squamous mucosa vs post-ablation neosquamous mucosa. Nineteen microRNAs were differentially expressed between post-ablation neosquamous and post-ablation squamous mucosa obtained from the more proximal non-treated esophageal segment. Twelve microRNAs were differentially expressed in both neosquamous vs matched proximal squamous mucosa and neosquamous vs squamous mucosa from healthy patients. Nine microRNAs (miR-424-5p, miR-127-3p, miR-98-5p, miR-187-3p, miR-495-3p, miR-34c-5p, miR-223-5p, miR-539-5p, miR-376a-3p, miR-409-3p) were expressed at higher levels in post-ablation neosquamous mucosa than in matched proximal squamous and healthy squamous mucosa. These microRNAs were also more highly expressed in Barrett's esophagus mucosa than matched proximal squamous and squamous mucosa from controls. Target prediction and pathway analysis suggests that these microRNAs may be involved in the regulation of cell survival signalling pathways. Three microRNAs (miR-187-3p, miR-135b-5p and miR-31-5p) were expressed at higher levels in post-ablation neosquamous mucosa than in matched proximal squamous and healthy squamous mucosa. These miRNAs were expressed at similar levels in pre-ablation Barrett's esophagus mucosa, matched proximal squamous and squamous mucosa from controls. Target prediction and pathway analysis suggests that these microRNAs may be involved in regulating the expression of proteins that contribute to barrier function.

CONCLUSION

Neosquamous mucosa arising after ablation of Barrett's esophagus expresses microRNAs that may contribute to decreased barrier function and microRNAs that may be involved in the regulation of survival signaling pathways.

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.

Incidence of metachronous visible lesions in patients referred for radiofrequency ablation (RFA) therapy for early Barrett's neoplasia: a single-centre experience

OBJECTIVE

Evaluate the incidence of metachronous visible lesions (VLs) in patients referred for radiofrequency ablation (RFA) for early Barrett's neoplasia.

DESIGN

This study was conducted as part of the service evaluation audit.

SETTING

Tertiary referral centre.

PATIENTS

All patients with dysplastic Barrett's oesophagus referred for RFA were included for analysis. White light high-resolution endoscopy (HRE), autofluorescence imaging and narrow band imaging were sequentially performed. Endoscopic mucosal resection (EMR) was performed for all VL. Three to six months after EMR, all patients underwent initial RFA and then repeat RFA procedures at three monthly intervals.

INTERVENTIONS

All endoscopy reports and final staging by EMR/surgery were evaluated and included for analysis.

RESULTS

Fifty patients were analysed; median age 73 years, 84% men. 38/50 patients (76%) had a previous EMR due to the presence of VL before referred for ablation; twelve patients had no previous treatment. In total, 151 ablation procedures were performed, median per patient 2.68. Twenty metachronous VL were identified in 14 patients before the first ablation or during the RFA protocol; incidence was 28%. All metachronous lesions were successfully resected by EMR. Upstaging after rescue EMR compared with the initial histology was observed in four patients (28%).

CONCLUSIONS

In total, 28% of patients enrolled in the RFA programme were diagnosed to have metachronous lesions. This high-incidence rate highlights the importance of a meticulous examination to identify and resect any VL before every ablation session. RFA treatment for early Barrett's neoplasia should be performed in tertiary referral centres with HRE and EMR facilities and expertise.

Prediction of response to endoscopic therapy of Barrett's dysplasia by using genetic biomarkers

BACKGROUND

Endoscopic therapy for the treatment of high-grade dysplasia (HGD) and intramucosal cancer (IMC) in Barrett's esophagus (BE) may not always result in complete remission of dysplasia (CRD).

OBJECTIVE

To determine whether genetic alterations in the Barrett's mucosa can predict response to endoscopic therapy.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care institution.

PATIENTS

Selected patients who underwent endoscopic therapy for BE containing HGD/IMC between 2003 and 2010.

INTERVENTIONS

Endoscopic therapy combining mucosal resection and different ablation modalities was performed based on patient characteristics, endoscopic findings, and technique evolution. Fluorescence in situ hybridization was used to evaluate genetic alterations on baseline endoscopic cytology brushings by using probes directed to loci 8q24 (MYC), 9p21 (CDKN2A; alias P16), 17q12 (ERBB2; alias Her-2/neu), and 20q13.2 (ZNF217).

MAIN OUTCOME MEASUREMENTS

Genetic biomarkers predicting achievement of CRD after endoscopic therapy.

RESULTS

A total of 181 patients were included (145 men; 66 ± 10 years of age). There were 130 patients (72%) who responded to endoscopic therapy with CRD. Multiple gains detected by fluorescence in situ hybridization was found to be a negative predictor (hazard ratio 0.57; 95% confidence interval, 0.40-0.82) after adjusting for potential clinical confounders. Similar results were found when analyses were restricted to patients (n = 66) undergoing radiofrequency ablation (hazard ratio 0.58; 95% confidence interval, 0.31-1.09).

LIMITATIONS

Retrospective study, heterogeneity of treatment modalities.

CONCLUSION

Patients with multiple gains detected by brush cytology specimens may have a lower response rate to endoscopic therapy. The presence of multiple gains can be an adjunct to standard histology in prognosticating BE patients with HGD/IMC undergoing endoscopic therapy.

British Society of Gastroenterology guidelines on the diagnosis and management of Barrett's oesophagus

These guidelines provide a practical and evidence-based resource for the management of patients with Barrett's oesophagus and related early neoplasia. The Appraisal of Guidelines for Research and Evaluation (AGREE II) instrument was followed to provide a methodological strategy for the guideline development. A systematic review of the literature was performed for English language articles published up until December 2012 in order to address controversial issues in Barrett's oesophagus including definition, screening and diagnosis, surveillance, pathological grading for dysplasia, management of dysplasia, and early cancer including training requirements. The rigour and quality of the studies was evaluated using the SIGN checklist system. Recommendations on each topic were scored by each author using a five-tier system (A+, strong agreement, to D+, strongly disagree). Statements that failed to reach substantial agreement among authors, defined as >80% agreement (A or A+), were revisited and modified until substantial agreement (>80%) was reached. In formulating these guidelines, we took into consideration benefits and risks for the population and national health system, as well as patient perspectives. For the first time, we have suggested stratification of patients according to their estimated cancer risk based on clinical and histopathological criteria. In order to improve communication between clinicians, we recommend the use of minimum datasets for reporting endoscopic and pathological findings. We advocate endoscopic therapy for high-grade dysplasia and early cancer, which should be performed in high-volume centres. We hope that these guidelines will standardise and improve management for patients with Barrett's oesophagus and related neoplasia.

Endoscopic resection (endoscopic submucosal dissection/endoscopic mucosal resection) for superficial Barrett's esophageal cancer

Recently developed endoscopic resection (endoscopic submucosal dissection [ESD]/ endoscopic mucosal resection) has dramatically changed the therapeutic approach for Barrett's esophageal cancer. The rationale for endoscopic resection is that lesions confined to the mucosal layer have negligible risk for developing lymph node metastasis and can be successfully eradicated by endoscopic treatment as a curative treatment with minimal invasiveness. According to some reports that analyzed the rate of lymph-node involvement relative to the depth of mucosal or submucosal tumor infiltration, endoscopic resection is clearly indicated for intramucosal carcinoma and might be extended to lesions with invasion into the submucosa (<200 μm, sm1) because of the low risk for lymph node metastasis. Most Japanese experts recommend ESD for Barrett's esophageal cancer after accurate diagnosis of the margin of cancer using narrow band imaging with magnifying endoscopy because of its high curative rate. However, few studies have evaluated the long-term outcomes of endoscopic resection for Barrett's esophageal cancer in Japan. Further investigations should be conducted to establish endoscopic resection for Barrett's esophageal cancer.

Correlation of the presence and extent of loss of heterozygosity mutations with histological classifications of Barrett's esophagus

Background

Recent advances in the management of Barrett’s Esophagus (BE) have placed greater emphasis on accurate diagnosis of BE as well as better prediction of risk for progression to esophageal adenocarcinoma (EAC). Histological evaluation of BE is particularly challenging with significant inter-observer variability. We explored the presence and extent of genomic instability in BE biopsy specimens as a means to add supplementary information to the histological classification and clinical decision-making related to early disease.

Methods

We reviewed histology slides from 271 patients known to have BE. Using histological features as a guide, we microdissected target cell populations with various histological classifications of BE (intestinal metaplasia, “indefinite for dysplasia”, low grade dysplasia, or high grade dysplasia). DNA was extracted from microdissected targets and analyzed for loss of heterozygosity (LOH) using a panel of 16 LOH mutational markers associated with tumor suppressor genes at chromosomal loci 1p, 3p, 5q, 9p, 10q, 17p, 17q, 18q, 21q, 22q. The presence or absence of mutations and the clonality of each mutation were determined for each marker.

Results

The presence and clonal expansion of LOH mutations was formulated into mutational load (ML) for each microdissected target analyzed. ML correlated with the histological classification of microdissected targets, with increasingly severe histology having higher ML. Three levels of mutation load (no ML, low ML, and high ML) were defined based on the population of microdissected targets histologically classified as intestinal metaplasia. All microdissected targets with dysplasia had mutations, with a high ML consistently present in high grade dysplasia targets. Microdissected targets histologically classified as intestinal metaplasia or “indefinite for dysplasia” spanned a range of no, low, and high ML.

Conclusions

The results of this study reinforce the association of genomic instability with disease progression in BE. The presence and extent (clonality) of genomic instability, as assessed by mutational load, may assist histology in defining early stages of BE that are potentially at greater risk for disease progression. Assessment of mutational load using our panel of LOH mutational markers may be a useful adjunct to microscopic inspection of biopsy specimens, and thereby, improve patient management.

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.

Barrett's esophagus: endoscopic treatments I

The following on endoscopic treatments of Barrett's esophagus includes commentaries on indications for endoscopic treatments; endo-luminal plication procedures; the cellular modifications induced by the endoscopic ablation therapies; eradication by banding without resection; the evaluation of complete ablation; recurrence after ablation; association of antireflux surgery; radiofrequency ablation; and nondysplastic Barrett's esophagus.

Endoscopic resection techniques and ablative therapies for Barrett's neoplasia

Esophageal adenocarcinoma is the most rapidly increasing cancer in western countries. High-grade dysplasia (HGD) arising from Barrett's esophagus (BE) is the most important risk factor for its development, and when it is present the reported incidence is up to 10% per patient-year. Adenocarcinoma in the setting of BE develops through a well known histological sequence, from non-dysplastic Barrett's to low grade dysplasia and then HGD and cancer. Endoscopic surveillance programs have been established to detect the presence of neoplasia at a potentially curative stage. Newly developed endoscopic treatments have dramatically changed the therapeutic approach of BE. When neoplasia is confined to the mucosal layer the risk for developing lymph node metastasis is negligible and can be successfully eradicated by an endoscopic approach, offering a curative intention treatment with minimal invasiveness. Endoscopic therapies include resection techniques, also known as tissue-acquiring modalities, and ablation therapies or non-tissue acquiring modalities. The aim of endoscopic treatment is to eradicate the whole Barrett's segment, since the risk of developing synchronous and metachronous lesions due to the persistence of molecular aberrations in the residual epithelium is well established.

Biomarker-based prediction of inflammatory bowel disease-related colorectal cancer: a case-control study

Background

Regular colonoscopic surveillance for detection of dysplasia is recommended in longstanding inflammatory bowel disease (IBD), however, its sensitivity is disputed. Screening accuracy may increase by using a biomarker-based surveillance strategy.

Methods

A case-control study was performed to determine the prognostic value of DNA ploidy and p53 in IBD-related neoplasia. Cases with IBD-related colorectal cancer (CRC), detected in our surveillance program between 1985-2008, were selected and matched with two controls, for age, gender, disease characteristics, interval of follow-up, PSC, and previous surgery. Biopsies were assessed for DNA ploidy, p53, grade of inflammation and neoplasia. Progression to neoplasia was analyzed with Cox regression analysis, adjusting for potentially confounding variables.

Results

Adjusting for age, we found statistically significant Hazard ratios (HR) between development of CRC, and low grade dysplasia (HR5.5; 95%CI 2.6-11.5), abnormal DNA ploidy (DNA index (DI) 1.06-1.34, HR4.7; 95%CI 2.9-7.8 and DI>1.34, HR6.6; 95%CI 3.7-11.7) and p53 immunopositivity (HR3.0; 95%CI 1.9-4.7) over time. When adjusting for all confounders, abnormal DNA ploidy (DI 1.06-1.34, HR4.7; 95%CI 2.7-7.9 and DI>1.34, HR5.0; 95%CI 2.5-10.0) and p53 immunopositivity (HR1.7; 95%CI 1.0-3.1) remained statistically significant predictive of neoplasia.

Conclusion

In longstanding IBD, abnormal DNA ploidy and p53 immunopositivity are important risk factors of developing CRC. The yield of surveillance may potentially increase by adding these biomarkers to the routine assessment of biopsies.

Effectiveness, safety, and cost-effectiveness of photodynamic therapy in Barrett's esophagus: a systematic review

Barrett's esophagus, the management of which remains controversial, is the precursor condition to esophageal adenocarcinoma. A number of endoscopic treatments have been designed as an alternative to surgical resection for patients with high-grade dysplasia. One of these, photodynamic therapy, involves the light activation of a photosensitizer that causes local tissue destruction via oxidation reactions. The present work reviews the effectiveness, safety, and cost-effectiveness of this treatment. A systematic review of the literature recorded in the Medline, Embase, the Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Database, and the National Health Service Economic Evaluation Database was undertaken. Articles reporting randomized clinical trials of photodynamic therapy for the treatment of Barrett's esophagus, and economic assessments of the procedure, were selected. The quality of the articles was checked. Twelve articles were included in this review: eight randomized, controlled clinical trials and four economic assessments. The clinical trials suffered from methodological limitations, but the economic assessments were considered to be good quality. Photodynamic therapy is effective for the ablation of dysplasia in Barrett's esophagus, although the frequency of adverse events is quite high. The procedure is presented as a cost-effective alternative to intense endoscopic monitoring and esophagectomy. However, the evidence regarding its effectiveness in reducing the number of patients who go on to develop cancer is only incipient. Rigorous, controlled studies with longer follow-up times, in which photodynamic therapy is compared with surgical resection and other endoscopic techniques, are needed.

Prevalence and predictors of recurrent neoplasia after ablation of Barrett's esophagus

BACKGROUND

The incidence and risk factors for recurrence of dysplasia after ablation of Barrett's esophagus (BE) have not been well defined.

OBJECTIVE

To determine the rate and predictors of dysplasia/neoplasia recurrence after photodynamic therapy (PDT) in BE.

SETTING

Retrospective analysis of a prospective cohort of BE patients seen at a specialized BE unit.

METHODS

Patients underwent a standard protocol assessment with esophagogastroduodenoscopy and 4-quadrant biopsies every centimeter at 3-month intervals after ablation. Recurrence was defined as the appearance of any grade of dysplasia or neoplasia after 2 consecutive endoscopies without dysplasia. Entry histology, demographics, length of BE, presence and length of diaphragmatic hernia, EMR, stricture formation, nonsteroidal anti-inflammatory drug use, smoking, and the presence of nondysplastic BE or squamous epithelium were assessed for univariate associations. Time-to-recurrence analysis was done by using Cox proportional hazards regression. A multivariate model was constructed to establish independent associations with recurrence.

RESULTS

A total of 363 patients underwent PDT with or without EMR. Of these, 261 patients were included in the final analysis (44 lost to follow-up, 46 had residual dysplasia, and 12 had no dysplasia at baseline). Indication for ablation was low-grade dysplasia (53 patients, 20%), high-grade dysplasia (152 patients, 58%), and intramucosal cancer (56 patients, 21%). Median follow-up was 36 months (interquartile range 18-79 months). Recurrence occurred in 45 patients. Median time to recurrence was 17 months (interquartile range 8-45 months). Significant predictors of recurrence on the multivariate model were older age (hazard ratio [HR] 1.04, P=.029), presence of residual nondysplastic BE (HR 2.88, P=.012), and a history of smoking (HR 2.68, P=.048).

LIMITATIONS

Possibility of missing prevalent dysplasia despite aggressive surveillance.

CONCLUSION

Recurrence of dysplasia/neoplasia after PDT ablation is associated with advanced age, smoking, and residual BE.

Biomarkers in Barrett's Esophagus

Biomarkers are substances that can be used to indicate normal or diseased states. In clinical settings, the term biomarker generally refers to a molecular marker produced by tissues whose detection heralds a diseased state. For patients with Barrett's esophagus, there are at least three clinical settings in which the use of molecular biomarkers has been proposed including 1) stratifying the risk of neoplastic progression, 2) serving as an adjunct to aid in the diagnosis of dysplasia, and 3) predicting response to ablative therapies. Although the routine clinical use of biomarkers in any of these clinical settings is not yet recommended, it seems reasonable to assume that biomarker validation studies will be carried out in the coming years and that movement into the clinics will be inevitable. This article reviews the current progress in using biomarkers in each of the clinical settings described above with a focus on the molecular biomarkers which have advanced the farthest toward use in routine clinical practice.

Treatment for Barrett's oesophagus

BACKGROUND

Treatments for Barrett's oesophagus, the precursor lesion of adenocarcinoma, are available but whether these therapies effectively prevent the development of adenocarcinoma, and in some cases eradicate the Barrett's oesophagus segment, remains unclear.

OBJECTIVES

To summarise, quantify and compare the efficacy of pharmacological, surgical and endoscopic treatments for the eradication of dysplastic and non-dysplastic Barrett's oesophagus and prevention of these states from progression to adenocarcinoma.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2004, issue 4), MEDLINE (1966 to June 2008) and EMBASE (1980 to June 2008).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing medical, endoscopic or non-resectional surgical treatments for Barrett's oesophagus. The primary outcome measures were complete eradication of Barrett's and dysplasia at 12 months, and reduction in the number of patients progressing to cancer at five years or latest time point.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data and assessed the quality of the trials included in the analysis.

MAIN RESULTS

Sixteen studies, including 1074 patients, were included. The mean number of participants in the studies was small (n = 49; range 8 to 208). Most studies did not report on the primary outcomes. Medical and surgical interventions to reduce symptoms and sequelae of gastro-oesophageal reflux disease (GORD) did not induce significant eradication of Barrett's oesophagus or dysplasia. Endoscopic therapies (photodynamic therapy (PDT with aminolevulinic acid or porfimer sodium), argon plasma coagulation (APC) and radiofrequency ablation (RFA)) all induced regression of Barrett's oesophagus and dysplasia. The data for photodynamic therapy were heterogeneous with a mean eradication rate of 51% for Barrett's oesophagus and between 56% and 100% for dysplasia, depending on the treatment regimens. The variation in photodynamic therapy eradication rates for dysplasia was dependent on the drug, source and dose of light. Radiofrequency ablation resulted in eradication rates of 82% and 94% for Barrett's oesophagus and dysplasia respectively, compared to a sham treatment. Endoscopic treatments were generally well tolerated, however all were associated with some buried glands, particularly following argon plasma coagulation and photodynamic therapy, as well as photosensitivity and strictures induced by porfimer sodium based photodynamic therapy in particular.

AUTHORS' CONCLUSIONS

Despite their failure to eradicate Barrett's oesophagus, the role of medical and surgical interventions to reduce the troubling symptoms and sequelae of GORD is not questioned. Whether therapies for GORD reduce the cancer risk is not yet known. Ablative therapies have an increasing role in the management of dysplasia within Barrett's and current data would favour the use of radiofrequency ablation compared with photodynamic therapy. Radiofrequency ablation has been shown to yield significantly fewer complications than photodynamic therapy and is very efficacious at eradicating both dysplasia and Barrett's itself. However, long-term follow-up data are still needed before radiofrequency ablation can be used in routine clinical care without the need for very careful post-treatment surveillance. More clinical trial data and in particular randomised controlled trials are required to assess whether or not the cancer risk is reduced in routine clinical practice.

Aneuploidy and overexpression of Ki67 and p53 as markers for neoplastic progression in Barrett's esophagus: a case-control study

OBJECTIVES

Surveillance of patients with Barrett's esophagus (BE) aims at early detection and treatment of neoplastic changes, particularly esophageal adenocarcinoma (EAC). The histological evaluation of biopsy samples has its limitations, and biomarkers may improve early identification of BE patients at risk for progression to EAC. The aim of this study was to determine the predictive value of p53, Ki67, and aneuploidy as markers of neoplastic progression in BE.

METHODS

A total of 27 BE patients with histologically proven progression to high-grade dysplasia (HGD) or EAC (cases) and 27 BE patients without progression (controls) were selected and matched for age, gender, and duration of follow-up. Dysplasia grade was determined in 212 biopsy samples obtained during surveillance endoscopies from cases and in 231 biopsy samples collected from controls. DNA ploidy status was determined by flow cytometry, whereas Ki67 and p53 expression was determined by immunohistochemistry. Hazard ratios (HRs) were calculated by Cox regression adjusted for potentially confounding variables.

RESULTS

A univariate analysis showed that low-grade dysplasia (LGD) increased the risk of developing HGD/EAC compared with no dysplasia (HR 3.6; 95% confidence interval (CI): 1.6 - 8.1). Aneuploidy (HR 3.5; 95% CI: 1.3-9.4), strong Ki67 overexpression (HR 5.2; 95% CI: 1.5-17.6), and moderate p53 overexpression (HR 6.5; 95% CI: 2.5-17.1) were also associated with an increased risk of developing HGD/EAC, independent of the histological result. A multivariable analysis showed that in the presence of LGD, p53 overexpression, and to a lesser extent, Ki67 overexpression remained important risk factors for neoplastic progression, whereas aneuploidy was no longer predictive.

CONCLUSIONS

p53 overexpression and, to a lesser extent, Ki67 overexpression could predict neoplastic progression in BE irrespective of the histological result. These markers may be useful for identifying patients at an increased risk of developing EAC, either alone or used as a panel.

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.

Radiofrequency ablation of Barrett's esophagus: short-term results

BACKGROUND

The presence of Barrett's esophagus (BE) increases the risk of esophageal cancer. Total regression of BE is uncommon with medication or laparoscopic fundoplication, and endoscopic techniques to obliterate BE have varied results. This study evaluated the early results of a balloon-based catheter radiofrequency ablation (RFA) system in patients with medically refractory reflux symptoms and biopsy-proven BE.

METHODS

The medical records of 27 consecutive patients who underwent RFA for BE from March 2005 through January 2007 were reviewed. Esophagogastroduodenoscopy was performed before ablation to document presence of BE and no cancer and at 8 weeks after the RFA to assess the presence of residual BE.

RESULTS

Mean patient age was 53.6 +/- 12.5 years; 16 (59%) were men. The average length of the Barrett segment treated was 4.6 +/- 4.7 cm. Two patients (7.4%) had low-grade dysplasia. No patient had high-grade dysplasia and cancer. There was no periprocedural morbidity or at follow-up, no postprocedure dysphagia or stricture. In all patients, the BE was completely replaced with normal squamous epithelium. Symptoms regressed in 16 patients (60%) with RFA and proton pump inhibitor therapy. Eleven required an antireflux procedure for persistent symptoms.

CONCLUSIONS

Short-term results show that RFA for BE is safe and achieves 100% replacement of intestinal metaplasia. RFA of BE combined with fundoplication may be offered to patients with BE and medically refractory reflux symptoms. Long-term endoscopic surveillance is needed to determine if the risk of cancer is reduced with this bimodality therapy.

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.

Argon plasma coagulation under magnifying chromoendoscopy for gastric premalignant lesions: an analysis of 90 cases

AIM: To investigate the effects and clinical value of argon plasma coagulation (APC) on gastric premalignant lesions under magnifying chromoendoscopy (MCE).

METHODS: A total of 90 cases with gastric premalignant lesions underwent argon plasma coagulation under magnifying chromoendoscopy using Fujinon EG-590ZW magnifying endoscope in combination with methylene blue staining. The changes of microstructures after treatment were studied and compared with histopathology.

RESULTS: Six months after argon plasma coagulation treatment, microstructures of gastric mucosa in 90 cases with intestinal metaplasia and dysplasia were regenerated from type E, F to type C or D (86.7%, 6.7%), and the abnormal hyperplasia blood capillary disappeared. Histopathological tissues changed into active inflammation (85.6%) or atrophic inflammation (8.9%). The ablation rates of microstructures (type E and F) and histopathology (intestinal metaplasia and dysplasia) were 93.0% and 94.4%, respectively.

CONCLUSION: Argon plasma coagulation is a safe and effective method in the treatment of gastric premalignant lesions.

A systematic review and meta-analysis of the treatment for Barrett's esophagus

As evidence-based strategies to the clinical management of Barrett's esophagus (BE) are lacking, we have carried out a systematic review and meta-analysis of all published randomized controlled trials with the aim of evaluating the value of different approaches in the treatment of BE. Searches were conducted in the databases PUBMED, EMBASE, and Cochrane Library. Thirteen randomized clinical trials that fulfilled the inclusion criteria and addressed the clinical questions of this analysis were assessed in more detail. Based on our search, neither the pharmacological nor surgical therapies currently available for reflux appear to achieve complete regression of BE and the elimination of the cancer risk associated with it. In contrast, endoscopic ablative techniques are capable of achieving endoscopic and histological reversal of BE, with ablation by argon plasma coagulation (APC) appearing to be more effective than treatment with photodynamic therapy (PDT) [odds ratio (OR) 3.46, 95% confidence interval (CI) 1.67-7.81, P = 0.0008]. There was no statistically significant difference between APC and multipolar electrocoagulation (MPEC) in terms of the efficacy to achieve regression of BE (OR 2.01, 95% CI 0.77-5.23, P = 0.15). In conclusion, there have been only a limited number of randomized controlled trials that compare treatments for BE. The pharmacological therapy, antireflux surgery, and endoscopic ablative techniques are promising in terms of treating BE, but the studies carried out to date have had no adequate power to assess the effect of treatment on reducing and preventing progression to adenocarcinoma.

Correlation of histology with biomarker status after photodynamic therapy in Barrett esophagus

BACKGROUND

Currently, histology is used as the endpoint to define success with photodynamic therapy (PDT) in patients with high-grade dysplasia (HGD). Recurrences despite 'successful' ablation are common. The role of biomarkers in assessing response to PDT remains undefined. The objectives of the current study were 1) to assess biomarkers in a prospective cohort of patients with HGD/mucosal cancer before and after PDT and 2) to correlate biomarker status after PDT with histology.

METHODS

Patients who underwent PDT for HGD/mucosal cancer were studied prospectively. All patients underwent esophagogastroduodenoscopy, 4-quadrant biopsies every centimeter, endoscopic mucosal resection of visible nodules, and endoscopic ultrasound. Cytology samples were obtained by using standard cytology brushes. Biomarkers were assessed by using fluorescence in situ hybridization (FISH). The biomarkers that were assessed included loss of 9p21 (site of the p16 gene) and 17p13.1 (site of the p53 gene) loci; gains of the 8q24(c-myc), 17q (HER2-neu), and 20q13 loci; and multiple gains. Patients received PDT 48 hours after the administration of sodium porfimer. Demographic and clinical variables were collected prospectively. Patients were followed with endoscopy and repeat cytology for biomarkers. The McNemar test was used to compare biomarker proportions before and after PDT.

RESULTS

Thirty-one patients were studied. The median patient age was 66 years (interquartile range [IQR], 56-73 years), and 28 patients (88%) were men. The mean Barrett segment length was 5 cm (standard error of the mean, 0.5 cm). Post-PDT biomarkers were obtained after a median duration of 9 months (IQR, 3-12 months). There was a statistically significant decrease in the proportion of several biomarkers assessed after PDT. Six patients without HGD after PDT still had positive FISH results for 1 or more biomarkers: of these, 2 patients (33%) developed recurrent HGD.

CONCLUSIONS

In this initial study, histologic downgrading of dysplasia after PDT was associated with the loss of biomarkers that have been associated with progression of neoplasia in Barrett esophagus. Patients with persistently positive biomarkers appeared to be at a higher risk of recurrent HGD. These findings should be confirmed in a larger study.

Stepwise radical endoscopic resection of the complete Barrett's esophagus with early neoplasia successfully eradicates pre-existing genetic abnormalities

OBJECTIVES

Malignant transformation of Barrett's mucosa is associated with the accumulation of genetic alterations. Stepwise radical endoscopic resection of the Barrett's segment with early neoplasia is a promising new treatment resulting in complete re-epithelialization of the esophagus with neosquamous epithelium. It is unknown whether radical resection also eradicates genetic abnormalities. The aim of this study was to prospectively evaluate whether genetic abnormalities as found in the Barrett's segment before radical resection are effectively eradicated and absent in the neosquamous epithelium.

METHODS

Nine patients with early neoplasia who successfully underwent radical resection were included. Immunohistochemistry (IHC) was performed to assess p53 protein overexpression. DNA fluorescent in-situ hybridization was (DNA-FISH) performed for evaluation of numerical abnormalities of chromosomes 1 and 9, and losses of p16 and p53. Immunohistochemistry and DNA-FISH were performed on endoscopic resection specimens of the neoplasia and on follow-up biopsies of the neosquamous epithelium.

RESULTS

DNA-FISH and IHC showed alterations in the pretreatment samples of all patients. All showed aneusomy of chromosome 1 and 9. Loss of p16 and p53 were seen in 6 and 8 patients. IHC showed intense p53 nuclear staining in seven patients. Post-treatment biopsies showed neosquamous epithelium with a normal diploid signal count for all DNA-FISH probes and normal IHC stainings in all patients.

CONCLUSIONS

Radical resection of Barrett's esophagus with early neoplasia successfully eradicates pre-existing genetic abnormalities and results in neosquamous epithelium without these genetic abnormalities.

Protoporphyrin IX fluorescence photobleaching and the response of rat Barrett's esophagus following 5-aminolevulinic acid photodynamic therapy

Barrett's esophagus (BE) can experimentally be treated with 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT), in which ALA, the precursor of the endogenous photosensitizer protoporphyrin IX (PpIX) and subsequent irradiation with laser light are applied to destroy the (pre)malignant tissue. Accurate dosimetry is critical for successful ALA-PDT. Here, in vivo dosimetry and kinetics of PpIX fluorescence photobleaching were studied in a rat model of BE. The fluence and fluence rate were standardized in vivo and PpIX fluorescence was measured simultaneously at the esophageal wall during ALA-PDT and plotted against the delivered fluence rather than time. Rats with BE were administered 200 mg kg(-1) ALA (n = 17) or served as control (n = 4). Animals were irradiated with 633 nm laser light at a measured fluence rate of 75 mW cm(-2) and a fluence of 54 J cm(-2). Large differences were observed in the kinetics of PpIX fluorescence photobleaching in different animals. High PpIX fluorescence photobleaching rates corresponded with tissue ablation, whereas low rates corresponded with no damage to the epithelium. Attempts to influence tissue oxygenation by varying balloon pressure and ventilation were shown not to be directly responsible for the differences in effect. In conclusion, in vivo dosimetry is feasible in heterogeneous conditions such as BE, and PpIX fluorescence photobleaching is useful to predict the tissue response to ALA-PDT.

Prostate PDT dosimetry

We provide a review of the current state of dosimetry in prostate photodynamic therapy (PDT). PDT of the human prostate has been performed with a number of different photosensitizers and with a variety of dosimetry schemes. The simplest clinical light dose prescription is to quantify the total light energy emitted per length (J/cm) of cylindrical diffusing fibers (CDF) for patients treated with a defined photosensitizer injection per body weight. However, this approach does not take into account the light scattering by tissue and usually underestimates the local light fluence rate, and consequently the fluence. Techniques have been developed to characterize tissue optical properties and light fluence rates in vivo using interstitial measurements during prostate PDT. Optical methods have been developed to characterize tissue absorption and scattering spectra, which in turn provide information about tissue oxygenation and drug concentration. Fluorescence techniques can be used to quantify drug concentrations and photobleaching rates of photosensitizers.

Stepwise radical endoscopic resection is effective for complete removal of Barrett's esophagus with early neoplasia: a prospective study

OBJECTIVES

Endoscopic therapy for early neoplasia in Barrett's esophagus (BE) is evolving rapidly. Aim of this study was to prospectively evaluate safety and efficacy of stepwise radical endoscopic resection (ER) of BE containing early neoplasia.

METHODS

Patients with early neoplasia (i.e., high-grade intraepithelial neoplasia or early cancer) in BE < or = 5 cm, without signs of submucosal infiltration or lymph node/distant metastases, were included. Patients underwent resection sessions (cap technique after submucosal lifting) with intervals of 6 wk.

RESULTS

Between January 2003 and December 2004, 39 consecutive patients were included. Therapy was discontinued in two patients due to unrelated comorbidity. Complete eradication of early neoplasia was achieved in all 37 treated patients in a median number of three sessions. Complete removal of all Barrett's mucosa was achieved in 33 (89%) patients: 4 patients (all had undergone APC [argon plasma coagulation]) were found to have small isles of Barrett's mucosa underneath neosquamous mucosa. Complications occurred in two out of 88 (2%) ER procedures: one asymptomatic perforation, one delayed bleeding. Symptomatic stenosis occurred in 10 of 39 (26%) patients and was effectively treated by endoscopic bougienage. During a median follow-up of 11 months, no patients died and none had recurrence of neoplasia or Barrett's mucosa.

CONCLUSIONS

Stepwise radical ER is effective for selected patients with early neoplasia in BE; provides optimal histopathological diagnosis; and may reduce recurrence rate, since all mucosa at risk is effectively removed. Use of APC should be limited to prevent buried Barrett's mucosa. Methods for prevention of stenosis should be developed.

Multistage carcinogenesis in Barrett's esophagus

The multistage carcinogenesis of esophageal adenocarcinoma is a process of clonal evolution within Barrett's esophagus neoplasms. The initiating event for Barrett's esophagus is unknown, but is associated with chronic gastric reflux which probably also promotes progression. Inactivation of both alleles of CDKN2A appear to be early events causing clonal expansion. Clones with TP53 inactivated expand if they have already inactivated CDKN2A. After TP53 has been inactivated, tetraploid and aneuploid clones tend to develop. The final events that lead to invasion and metastasis are unknown. Evolutionary biology provides important tools to understand clonal evolution in progression and cancer prevention.

p53 and the malignant progression of Barrett's esophagus

Barrett's esophagus (BE) is a metaplastic disorder in which specialized columnar epithelium replaces healthy squamous epithelium (intestinal metaplasia). Even though its pathophysiology and the steps of its neoplastic progression are not completely understood, BE can be considered as a complication of gastroesophageal reflux disease (GERD). Given that esophageal adenocarcinoma, which is continually increasing in the Western world, still has a poor prognosis and suffers from late diagnosis, and because BE is a precancerous lesion, there is a strong need for good molecular markers of malignant progression in Barrett's metaplasia (BM). The aim of this review is to examine the published data regarding the role that assessment of p53 may play in the management of BE, trying to understand if it may be a useful marker to early diagnose BE malignant transformation.

Diagnostic and therapeutic endoscopy

Within the gastrointestinal tract, there is no shorter segment with a higher cancer incidence than the gastro-esophageal junction. Flexible endoscopy is the mainstay for diagnosis of early and advanced esophageal adenocarcinoma, for the treatment of early lesions, and also for the palliation of advanced cancer. New developments in endoscopy aim to improve the diagnosis and treatment of esophageal cancer. These include high resolution and magnification endoscopy in combination with chromendoscopy, and techniques based on modulation of the features of light bundles, such as narrow band imaging, fluorescence endoscopy, and elastic scattering spectroscopy. The value of these techniques for the surveillance of distal esophageal neoplasia needs further study. Furthermore, new methods of tissue sampling and evaluation are being studied to augment identification and staging of patients at risk for cancer. Finally, newer instruments may decrease patient burden during endoscopy, making screening and surveillance more acceptable from a patient's perspective. This review discusses the new developments in flexible endoscopy for diagnosis and therapy of early and advanced and advanced esophageal adenocarcinoma.

Genomic analysis of Barrett's esophagus after ablative therapy: persistence of genetic alterations at tumor suppressor loci

Barrett's esophagus (BE) is a major predisposing factor for the development of esophageal adenocarcinoma. Current strategies for treatment of BE, both dysplastic and nondysplastic, include photodynamic therapy (PDT) and argon plasma coagulation (APC). However, the effect of ablative therapy at the genetic level is unclear. We performed loss of heterozygosity (LOH) analysis of BE in baseline and follow-up biopsy specimens from 21 patients with BE (17 male, 4 female) treated with PDT and/or APC. At baseline, 14 patients had intestinal metaplasia without dysplasia (MET), 4 low-grade dysplasia (LGD) and 3 high-grade dysplasia (HGD). LOH was assessed using a panel of 9 polymorphic markers for evaluation of the P53 gene on 17p, P16 on 9p, DCC and SMAD4 on 18q and the APC gene on 5q. The tissue specimens obtained at baseline (t = 0) were analysed, as well as the first (t = 1; mean interval: 4 months) and last (t = 2; mean interval: 8 months) available biopsy with residual or recurrent BE after ablation. At t = 0, allelic loss was detected of 5q in 27%, 9p in 56%, 17p in 31% and 18q in 6% of informative cases. At t = 1 (18 patients with persistent MET and 3 with LGD) and at t = 2 (8 MET, 2 LGD), the LOH patterns were not statistically different from t = 0. Further, multiple genetic lineages before and after therapy were detected in 15 cases illustrating the multiclonal nature of BE. We conclude that recurrent and/or persistent BE after ablative therapy still contains genetic alterations associated with malignant progression to cancer. Therefore, the goal of treatment should be the complete elimination of Barrett's mucosa.

Laser ablation therapies for Barrett's esophagus

The metaplastic change of the normal squamous epithelium of the distal esophagus into a specialized columnar epithelium is known as Barrett's esophagus (BE) and is associated with an increased risk of adenocarcinoma of the esophagus. It is a frequent complication of gastroesophageal reflux disease (GERD) and up to 10% of patients with GERD suffer from BE. The progression to dysplasia increases the risk of cancer development and the annual risk of developing cancer in Barrett's esophagus is estimated to be 0.5% per year. The management of BE with high grade dysplasia (HGD) is controversial. Recent innovations in endoscopic therapy have allowed for the development of multiple endoscopic techniques, such as photodynamic therapy (PDT), argon plasma coagulation (APC), and endoscopic mucosal resection. In this article, we will discuss primarily photodynamic therapy, and other ablative technologies such as argon plasma coagulation in the treatment of BE.