Endoscopic ablation of Barrett's oesophagus: a randomized-controlled trial of photodynamic therapy vs. argon plasma coagulation

Comparison of interventions for Barrett's esophagus: A network meta-analysis

BACKGROUND AND OBJECTIVE

Barrett's esophagus (BE) is a precancerous condition that has the potential to develop into esophageal cancer (EC). Currently, there is a wide range of management options available for individuals at different pathological stages in Barrett's esophagus (BE). However, there is currently a lack of knowledge regarding their comparative efficacy. To address this gap, we conducted a network meta-analysis of published randomized controlled trials to examine the comparative effectiveness of all regimens.

METHODS

Data extracted from eligible randomized controlled trials were utilized in a Bayesian network meta-analysis to examine the relative effectiveness of BE's treatment regimens and determine their ranking in terms of efficacy. The ranking probability for each regimen was assessed using the surfaces under cumulative ranking values. The outcomes under investigation were complete ablation of BE, neoplastic progression of BE, and complete eradication of dysplasia.

RESULTS

We identified twenty-three RCT studies with a total of 1675 participants, and ten different interventions. Regarding complete ablation of non-dysplastic BE, the comparative effectiveness ranking indicated that argon plasma coagulation (APC) was the most effective regimen, with the highest SUCRA value, while surveillance and PPI/H2RA were found to be the least efficacious regimens. For complete ablation of BE with low-grade dysplasia, high-grade dysplasia, or esophageal cancer, photodynamic therapy (PDT) had the highest SUCRA value of 94.1%, indicating it as the best regimen. Additionally, for complete eradication of dysplasia, SUCRA plots showed a trend in ranking PDT as the highest with a SUCRA value of 91.2%. Finally, for neoplastic progression, radiofrequency ablation (RFA) and surgery were found to perform significantly better than surveillance. The risk of bias assessment revealed that 6 studies had an overall high risk of bias. However, meta-regression with risk of bias as a covariate did not indicate any influence on the model. In terms of the Confidence in Network Meta-Analysis evaluation, a high level of confidence was found for all treatment comparisons.

CONCLUSION

Endoscopic surveillance alone or PPI/H2RA alone may not be sufficient for managing BE, even in cases of non-dysplastic BE. However, APC has shown excellent efficacy in treating non-dysplastic BE. For cases of BE with low-grade dysplasia, high-grade dysplasia, or esophageal cancer, PDT may be the optimal intervention as it can induce regression of BE metaplasia and prevent future progression of BE to dysplasia and EC.

Endoscopic Management of Esophageal Cancer

Advances in technology and improved understanding of the pathobiology of esophageal cancer have allowed endoscopy to serve a growing role in the management of this disease. Precursor lesions can be detected using enhanced diagnostic modalities and eradicated with ablation therapy. Furthermore, evolution in endoscopic resection has provided larger specimens for improved diagnostic accuracy and offer potential for cure of early esophageal cancer. In patients with advanced esophageal cancer, endoluminal therapy can improve symptom burden and provide therapeutic options for complications such as leaks, perforations, and fistulas. The purpose of this review article is to highlight the role of endoscopy in the diagnosis, treatment, and palliation of esophageal cancer.

Hybrid APC in Combination With Resection for the Endoscopic Treatment of Neoplastic Barrett's Esophagus: A Prospective, Multicenter Study

INTRODUCTION

The current therapy of neoplastic Barrett's esophagus (BE) consists of endoscopic resection plus ablation, with radiofrequency ablation as the best studied technique. This prospective trial assesses a potential alternative, namely hybrid argon plasma ablation.

METHODS

Consecutive patients with neoplastic BE undergoing ablation after curative endoscopic resection (89.6%) or primarily were included into this prospective trial in 9 European centers. Up to 5 ablation sessions were allowed for complete eradication of BE (initial complete eradication of intestinal metaplasia [CE-IM]), by definition including BE-associated neoplasia, documented by 1 negative endoscopy with biopsies. The main outcome was the rate of initial CE-IM in intention-to-treat (ITT) and per-protocol (PP) samples at 2 years. The secondary end points were the rate of recurrence-free cases (sustained CE-IM) documented by negative follow-up endoscopies with biopsies and immediate/delayed adverse events.

RESULTS

One hundred fifty-four patients (133 men and 21 women, mean age 64 years) received a mean of 1.2 resection and 2.7 ablation sessions (range 1-5). Initial CE-IM was achieved in 87.2% of 148 cases in the PP analysis (ITT 88.4%); initial BE-associated neoplasia was 98.0%. On 2-year follow-up of the 129 successfully treated cases, 70.8% (PP) or 65.9% (ITT) showed sustained CE-IM; recurrences were mostly endoscopy-negative biopsy-proven BE epithelium and neoplasia in 3 cases. Adverse events were seen in 6.1%.

DISCUSSION

Eradication and recurrence rates of Barrett's intestinal metaplasia and neoplasia by means of hybrid argon plasma coagulation at 2 years seem to be within expected ranges. Final evidence in comparison to radiofrequency ablation can only be provided by a randomized comparative trial.

Argon plasma coagulation for Barrett's esophagus with low-grade dysplasia: a randomized trial with long-term follow-up on the impact of power setting and proton pump inhibitor dose

BACKGROUND

This study evaluated the impact of power setting and proton pump inhibitor (PPI) dose on efficacy and safety of argon plasma coagulation (APC) of Barrett's esophagus (BE) with low-grade dysplasia (LGD). METHODS : 71 patients were randomized to APC with power set at 90 W or 60 W followed by 120 mg or 40 mg omeprazole. The primary outcome was the rate of complete (endoscopic and histologic) ablation of BE at 6 weeks. Secondary outcomes included safety and long-term efficacy. RESULTS : Complete ablation rate in the 90 W/120 mg, 90 W/40 mg, and 60 W/120 mg groups was 78 % (18/23; 95 % confidence interval [CI] 61-95), 60 % (15/25; 95 %CI 41-79), 74 % (17/23; 95 %CI 56-92), respectively, at 6 weeks and 70 % (16/23; 95 %CI 51-88), 52 % (13/25; 95 %CI 32-72), and 65 % (15/23; 95 %CI 46-85) at 2 years post-treatment (differences not significant). Additional APC was required in 28 patients (23 residual and 5 recurrent BE). At median follow-up of 108 months, 66/71 patients (93 %; 95 %CI 87-99) maintained complete ablation. No high-grade dysplasia or adenocarcinoma developed. Overall, adverse events (97 % mild) did not differ significantly between groups. Chest pain/discomfort was more frequent in patients receiving 90 W vs. 60 W power (P < 0.001). One patient had esophageal perforation and two developed stenosis.

CONCLUSIONS

APC power setting and PPI dose did not impact efficacy and safety of BE ablation. Complete ablation of BE with LGD was durable in > 90 % of patients, without any evidence of neoplasia progression in the long term.

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]).

Endoscopic management of esophageal cancer

Esophageal cancer (EC) generally consists of squamous cell carcinoma (which arise from squamous epithelium) and adenocarcinoma (which arise from columnar epithelium). Due to the increased recognition of risk factors associated with EC and the development of screening programs, there has been an increase in the diagnosis of early EC. Early EC is amenable to curative therapy by endoscopy, which can be performed by either endoscopic resection or endoscopic ablation. Endoscopic resection consists of either endoscopic mucosal resection (preferred in cases of adenocarcinoma) or endoscopic submucosal dissection (preferred in cases of squamous cell carcinoma). Endoscopic ablation can be performed by either radiofrequency ablation, cryotherapy, argon plasma coagulation or photodynamic therapy, amongst others. Endoscopy can also assist in the management of complications post-esophageal surgery, such as anastomotic leaks and perforations. Finally, there is a growing role for endoscopy to manage end-of-life palliative symptoms, especially dysphagia. The growing use of esophageal stents, debulking therapy and dilation can assist in improving a patient’s quality of life. In this review, we examine the multiple roles of endoscopy in the management of patients with EC.

Endoscopic therapy for Barrett’s esophagus and early esophageal cancer: Where do we go from here?

Since Barrett’s esophagus is a precancerous condition, efforts have been made for its eradication by various ablative techniques. Initially, laser ablation was attempted in non-dysplastic Barrett’s esophagus and subsequently, endoscopic ablation using photodynamic therapy was used in Barrett’s patients with high-grade dysplasia who were poor surgical candidates. Since then, various ablative therapies have been developed with radiofrequency ablation having the best quality of evidence. Resection of dysplastic areas only without complete removal of entire Barrett’s segment is associated with high risk of developing metachronous neoplasia. Hence, the current standard of management for Barrett’s esophagus includes endoscopic mucosal resection of visible abnormalities followed by ablation to eradicate remaining Barrett’s epithelium. Although endoscopic therapy cannot address regional lymph node metastases, such nodal involvement is present in only 1% to 2% of patients with intramucosal adenocarcinoma in Barrett esophagus and therefore is useful in intramucosal cancers. Post ablation surveillance is recommended as recurrence of intestinal metaplasia and dysplasia have been reported. This review includes a discussion of the technique, efficacy and complication rate of currently available ablation techniques such as radiofrequency ablation, cryotherapy, argon plasma coagulation and photodynamic therapy as well as endoscopic mucosal resection. A brief discussion of the emerging technique, endoscopic submucosal dissection is also included.

Salvage Endoscopic Argon Plasma Coagulation After Chemoradiotherapy for Inoperable Esophageal Cancer

PURPOSE

The purpose of this study is to evaluate the effectiveness of salvage endoscopic argon plasma coagulation (APC) therapy for local failure occurring after definitive chemoradiotherapy (CRT) in patients with inoperable esophageal cancer.

PATIENTS AND METHODS

A total of 47 patients with esophageal squamous cell carcinoma received CRT from January 2009 through November 2011 in our hospital. Thirty-five of these patients were excluded because of long-term disease-free status or because they received salvage surgery, systemic chemotherapy, or best supportive care. The other 12 patients had local relapse (n=8) or residual lesions (n=4) after definitive CRT and received salvage APC therapy. Local failures after definitive CRT were divided into 2 groups: the superficial growth group (n=6) and the submucosal growth group (n=6). The primary endpoints were relapse-free survival and overall survival after 60 months of follow-up.

RESULTS

Six patients in the superficial growth group and 1 patient in submucosal growth group had a complete response after salvage APC. The rates of both relapse-free survival and overall survival were higher in the superficial growth group than in the submucosal growth group. No complications occurred after APC.

CONCLUSIONS

Salvage APC is a potentially curative treatment for patients who have local failure associated with superficial tumors after CRT for esophageal squamous cell carcinoma.

Subsquamous intestinal metaplasia is common in treatment-naïve Barrett's esophagus

BACKGROUND AND AIMS

Barrett's intestinal metaplasia may extend beneath normal squamous epithelium at the squamocolumnar junction (SCJ) and therefore escape surveillance biopsy sampling. The prevalence of subsquamous intestinal metaplasia (SSIM) in patients undergoing Barrett's esophagus (BE) surveillance is unknown. Our aim was to examine the prevalence and distribution of SSIM proximal to the SCJ in patients undergoing BE surveillance.

METHODS

We enrolled consecutive patients with biopsy specimen-proven BE. Biopsy specimens were obtained from the squamous epithelium at 5 mm and 10 mm above the SCJ. The primary outcomes were the proportion of patients with SSIM at each level. We further assessed factors associated with SSIM.

RESULTS

We examined 515 squamous epithelial biopsy specimens from 106 BE patients (95% men; mean age, 66 years) with a mean Barrett's length of 3.0 cm. SSIM was present in 39% at 5 mm (95% CI, 29.4-48.6) and 21% (95% CI, 11.7-32.1) at 10 mm proximal to the SCJ. Among all biopsy specimens, 13% (95% CI, 10.6-16.6) contained SSIM: 17% (95% CI, 13-21.6) of biopsy samples at 5 mm and 8% (95% CI, 4.3-12.2) at 10 mm proximal to the SCJ. SSIM was more common in the anterior/right lateral position compared with the posterior/left lateral position (21% vs 11%, P = .001). None of the biopsy specimens showed dysplasia. Length of BE or duration of reflux symptoms were not associated with the presence of SSIM.

CONCLUSIONS

This cross-sectional study found a surprisingly high proportion of SSIM in treatment-naïve patients proximal to the SCJ. These findings raise questions regarding BE management and the prevalence of SSIM in normal-appearing esophagus.

Endoscopic Eradication Therapy in Barrett's Esophagus

Endoscopic eradication therapy (EET), the standard of care for treatment of Barrett's esophagus with dysplasia and early neoplasia, consists of a combination of endoscopic resection and ablative modalities. Resection techniques primarily include endoscopic mucosal resection or endoscopic submucosal dissection. Resection of nodular disease is generally followed by one of multiple ablative therapies among which radiofrequency ablation has the best evidence supporting safety and efficacy. These advanced endoscopic procedures require both experience and expertise in the cognitive and procedural aspects of EET. However, very few formal programs exist that teach endoscopists the necessary skills to perform EET in a safe, standardized, and efficacious manner. Case volume at both the endoscopist and center level has been shown to impact clinical outcomes based on limited data. As a result, some recent guidelines endorse case volume as a measure of competency. Quality indicators, which can be used as benchmarks for training and as part of pay for quality initiatives, have recently been derived for EET. However, quality metrics in EET have not been widely accepted, nor are they broadly used currently. While the efficacy of EET for BE is established, there is a need for application of quality metrics to both assure adequate training in these procedures, as well as to assess treatment outcomes. A standardized EET training curriculum during endoscopic training, with competency assessment of both new clinicians and endoscopists in practice has potential to improve care in EET.

Role of endoscopy in early oesophageal cancer

Incidence of oesophageal adenocarcinoma has increased exponentially in the West over the past few decades. Following detection of advanced cancers, 5-year survival rates remain bleak, making identification of early neoplasia, which has a better outcome, important. Detection of subtle oesophageal lesions during endoscopy can be challenging, and advanced imaging techniques might improve their detection. High-definition endoscopy has become a standard in most endoscopy centres, and this technology probably provides better delineation of mucosal features than standard-definition endoscopy. Various image enhancement techniques are now available with the development of new electronics and software systems. Image enhancement with chromoendoscopy using dyes has been a cost-effective option for many years, yet these techniques have been replaced in some contexts by electronic chromoendoscopy, which can be used with the press of a button. However, Lugol's chromoendoscopy remains the gold standard to identify squamous dysplasia. Identification and characterization of subtle neoplastic lesions could help to target biopsies and perform endoscopic resection for better local staging and definitive therapy. In vivo histology with techniques such as confocal endomicroscopy could make endotherapy feasible within a shorter timescale than when relying on histology on tissue samples. Once early neoplasia is identified, treatments include endoscopic resection, endoscopic submucosal dissection or various ablative techniques. Endotherapy has the advantage of being a less invasive technique than oesophagectomy, and is associated with lower mortality and morbidity. Endoscopic ablation therapies have evolved over the past few years, with radiofrequency ablation showing the best results in terms of success rates and complications in Barrett dysplasia.

Ablative therapy for esophageal dysplasia and early malignancy: focus on RFA

Ablative therapies have been utilized with increasing frequency for the treatment of Barrett's esophagus with and without dysplasia. Multiple modalities are available for topical ablation of the esophagus, but radiofrequency ablation (RFA) remains the most commonly used. There have been significant advances in technique since the introduction of RFA. The aim of this paper is to review the indications, techniques, outcomes, and most common complications following esophageal ablation with RFA.

Endoscopic Optical Coherence Tomography for Clinical Gastroenterology

Optical coherence tomography (OCT) is a real-time optical imaging technique that is similar in principle to ultrasonography, but employs light instead of sound waves and allows depth-resolved images with near-microscopic resolution. Endoscopic OCT allows the evaluation of broad-field and subsurface areas and can be used ancillary to standard endoscopy, narrow band imaging, chromoendoscopy, magnification endoscopy, and confocal endomicroscopy. This review article will provide an overview of the clinical utility of endoscopic OCT in the gastrointestinal tract and of recent achievements using state-of-the-art endoscopic 3D-OCT imaging systems.

How good is the neosquamous epithelium?

BACKGROUND/AIMS

Endoscopic radiofrequency ablation of dysplastic Barrett's esophagus (BE) combined with proton pump inhibitor therapy is commonly utilized for preventing progression of dysplastic BE to esophageal adenocarcinoma. Fundamental to the success of this and all ablative approaches is the healing of the ablated areas of BE with a stratified squamous epithelium referred to as 'neosquamous epithelium' (NSE). Although NSE appears 'normal' endoscopically, the reemergence of BE over time in the previously ablated segments raises the question of the health and integrity of NSE.

METHODS

The health of NSE was recently investigated in endoscopic biopsies in vitro in a group of patients after ablation while on proton pump inhibitors. Biopsies of NSE were compared to upper squamous epithelium (USE) from the same patients morphologically (light microscopy) and with respect to barrier function by measuring electrical resistance and fluorescein flux in mini-Ussing chambers.

RESULTS

Compared to USE, NSE exhibited dilated intercellular spaces and inflammation and defective barrier function by low electrical resistance and high fluorescein flux. Moreover, NSE exhibited downregulation of claudin-4, a highly expressed protein in squamous tight junctions.

CONCLUSION

NSE has defective barrier function in part due to downregulation of claudin-4. Since downregulation of claudin-4 increases paracellular permeability to cations, e.g. hydrogen ions, NSE is more vulnerable to attack and damage by acidic and weakly acidic refluxates--a phenomenon that may contribute in part to the reemergence of BE.

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.

Photodynamic Therapy for Barrett's Esophagus and Esophageal Carcinoma

This paper reviews the use of photodynamic therapy (PDT) in patients with Barrett's esophagus and esophageal carcinoma. We describe the history of PDT, mechanics, photosensitizers for PDT in patients with esophageal disease. Finally, we discuss its utility and limitations in this setting.

Endoscopic therapy of Barrett esophagus

Barrett esophagus (BE) is a well-established premalignant condition for esophageal adenocarcinoma (EAC), a lethal cancer with a dismal survival rate. The current guidelines recommend surveillance of patients with BE to detect dysplasia or early cancer before the development of invasive EAC. Recently, endoscopic eradication therapies have been shown to be safe and effective in the treatment of BE-related high-grade dysplasia and early EAC. This article reviews the various treatment options for BE and discusses the current evidence and gaps in knowledge in the understanding of treatment of this condition. In addition, recommendations are provided in context to the recently published guidelines by the American Gastroenterological Association.

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.

Ablation of Barrett's oesophagus: towards improved outcomes for oesophageal cancer?

Barrett's oesophagus is the major risk factor for the development of oesophageal adenocarcinoma. The management of Barrett's oesophagus entails treating reflux symptoms with acid-suppressing medication or surgery (fundoplication). However, neither form of anti-reflux therapy produces predictable regression, or prevents cancer development. Patients with Barrett's oesophagus usually undergo endoscopic surveillance, which aims to identify dysplastic changes or cancer at its earliest stage, when treatment outcomes should be better. Alternative endoscopic interventions are now available and are suggested for the treatment of early cancer and prevention of progression of Barrett's oesophagus to cancer. Such treatments could minimize the risks associated with oesophagectomy. The current status of these interventions is reviewed. Various endoscopic interventions have been described, but with long-term outcomes uncertain, they remain somewhat controversial. Radiofrequency ablation of dysplastic Barrett's oesophagus might reduce the risk of cancer progression, although cancer development has been reported after this treatment. Endoscopic mucosal resection (EMR) allows a 1.5-2 cm diameter piece of oesophageal mucosa to be removed. This provides better pathology for diagnosis and staging, and if the lesion is confined to the mucosa and fully excised, EMR can be curative. The combination of EMR and radiofrequency ablation has been used for multifocal lesions, but long-term outcomes are unknown. The new endoscopic interventions for Barrett's oesophagus and early oesophageal cancer have the potential to improve clinical outcomes, although evidence that confirms superiority over oesphagectomy is limited. Longer-term outcome data and data from larger cohorts are required to confirm the appropriateness of these procedures.

Diagnosis and management of Barrett's esophagus

Barrett esophagus is characterized by the replacement of squamous mucosa in the esophagus by specialized intestinal metaplasia. Its clinical significance lies in it being the strongest risk factor for and known precursor for esophageal adenocarcinoma. Diagnosis requires endoscopic confirmation of columnar metaplasia in the distal esophagus and histologic confirmation of specialized intestinal metaplasia. Recommendations for the management of subjects diagnosed with Barrett esophagus include periodic endoscopic surveillance to detect the development of high-grade dysplasia or adenocarcinoma. Careful endoscopic evaluation with high-resolution endoscopy and endoscopic resection is recommended in the evaluation of subjects with high-grade dysplasia and early adenocarcinoma.

Diagnosis and management of Barrett's esophagus

Barrett esophagus is characterized by the replacement of squamous mucosa in the esophagus by specialized intestinal metaplasia. Its clinical significance lies in it being the strongest risk factor for and known precursor for esophageal adenocarcinoma. Diagnosis requires endoscopic confirmation of columnar metaplasia in the distal esophagus and histologic confirmation of specialized intestinal metaplasia. Recommendations for the management of subjects diagnosed with Barrett esophagus include periodic endoscopic surveillance to detect the development of high-grade dysplasia or adenocarcinoma. Careful endoscopic evaluation with high-resolution endoscopy and endoscopic resection is recommended in the evaluation of subjects with high-grade dysplasia and early adenocarcinoma.

Adequacy of esophageal squamous mucosa specimens obtained during endoscopy: are standard biopsies sufficient for postablation surveillance in Barrett's esophagus?

BACKGROUND

After endoscopic eradication therapy (EET) for Barrett's esophagus (BE), surveillance of residual/recurrent intestinal metaplasia/dysplasia including subsquamous tissue is performed by using biopsy forceps.

OBJECTIVE

The goal of this study was to compare the adequacy of biopsy specimens obtained from neo-squamous (post-EET patients) and native (non-BE patients) squamous mucosa.

DESIGN

A case-control study using squamous biopsy specimens obtained at 2 tertiary referral centers was conducted.

INTERVENTIONS

Two experienced GI pathologists reviewed specimens from patients with neo- (post-EET patients) and native (non-BE patients) squamous mucosa in a blinded fashion after developing standardized criteria to assess tissue depth.

MAIN OUTCOME MEASUREMENTS

The primary outcome was the proportion of biopsy specimens that contained any amount of lamina propria.

RESULTS

A total of 193 biopsy specimens (1692 tissue pieces) from 104 patients were reviewed: 163 neo- and 30 native squamous. Of all biopsy specimens, only 37% contained any amount of lamina propria, and, furthermore, fewer than 4% of specimens had sufficient lamina propria (ie, more than two thirds of the entire squamous tissue present). When examining individual squamous tissue pieces, fewer than 11% contained lamina propria. No statistically significant differences in the presence of lamina propria were detected between neo- and native squamous mucosa.

CONCLUSION

The majority of esophageal squamous biopsy specimens obtained during endoscopy do not demonstrate lamina propria and subepithelial structures. This is true for both neo- and native squamous mucosa. Biopsy specimens of neo-squamous mucosa obtained after EET appear to be inadequate to exclude subsquamous intestinal metaplasia/dysplasia because lamina propria is not present in more than 60% of specimens. This has larger implications in the clinical management of BE patients after EET.

Buried metaplasia after endoscopic ablation of Barrett's esophagus: a systematic review

OBJECTIVES

Endoscopic ablation of Barrett's esophagus can bury metaplastic glands under a layer of neosquamous epithelium. To explore the frequency and importance of buried metaplasia, we have conducted a systematic review of reports on endoscopic ablation.

METHODS

We performed computerized and manual searches for articles on the results of photodynamic therapy (PDT) and radiofrequency ablation (RFA) for Barrett's esophagus. We extracted information on the number of patients treated, biopsy protocol, biopsy depth, and frequency of buried metaplasia.

RESULTS

We found 9 articles describing 34 patients with neoplasia appearing in buried metaplasia (31 after PDT). We found five articles describing a baseline prevalence of buried metaplasia (before ablation) ranging from 0% to 28%. In 22 reports on PDT for 953 patients, buried metaplasia was found in 135 (14.2%); in 18 reports on RFA for 1,004 patients, buried metaplasia was found in only 9 (0.9%). A major problem limiting the conclusions that can be drawn from these reports is that they do not describe specifically how frequently biopsy specimens contained sufficient subepithelial lamina propria to be informative for buried metaplasia.

CONCLUSIONS

Endoscopic ablation can bury metaplastic glands with neoplastic potential but, even without ablation, buried metaplasia often is found in areas where Barrett's epithelium abuts squamous epithelium. Buried metaplasia is reported less frequently after RFA than after PDT. However, available reports do not provide crucial information on the adequacy of biopsy specimens and, therefore, the frequency and importance of buried metaplasia after endoscopic ablation remain unclear.

Ablative therapies for Barrett's esophagus

Barrett's esophagus has gained increased clinical attention because of its association with esophageal adenocarcinoma, a cancer with increasing incidence and poor survival rates. The goals of ablating Barrett's esophagus are to decrease esophageal cancer rates and to improve overall survival and quality of life. Different techniques have been developed and tested for their effectiveness eradicating Barrett's epithelium. This review assesses the literature associated with different ablative techniques. The safety and efficacy of different techniques are discussed. This review concludes with recommendations for the clinician, including specific strategies for patient care decisions for patients with Barrett's esophagus with varying degrees of dysplasia.

Barrett's esophagus: endoscopic treatments II

The following on endoscopic treatments of Barrett's esophagus includes commentaries on animal experiments on cryotherapy; indications for cryotherapy, choice of dosimetry, number of sessions, and role in Barrett's esophagus and adenocarcinoma; recent technical developments of RFA technology and long-term effects; the comparative effects of diverse ablation procedures and the rate of recurrence following treatment; and the indications for treatment of dysplasia and the role of radiofrequency ablation.

[Endoscopic treatments for Barrett oesophagus]

High grade dysplasia and superficial carcinomas (with no extension under muscularis mucosae) can be indications for endoscopic treatments of Barrett oesophagus. When an endoscopic treatment is considered, a gastroscopy with use of acetic acid and planimetry and the confirmation of high-grade dysplasia by a new examination after PPI treatment and a pathologic second confirmation is needed. For high-grade dysplasia in focalised and visible lesions, an endoscopic resection by EMR or ESD should be proposed: it allows a more accurate pathologic examination and can be an effective curative treatment. After endoscopic resection of visible high grade dysplasia lesions, a complete eradication of Barrett oesophagus may be proposed to prevent dysplasia recurrence. In case of extensive high-grade dysplasia or to eradicate Barrett oesophagus residual lesions, radiofrequency ablation is the preferred endoscopic technique. Photodynamic therapy may also be proposed for more invasive lesions or after other endoscopic techniques with mucosal scars. Surgical oesophagus resection is still recommended for diffuse high-grade dysplasia in young patients or in case of pathologic pejorative criteria in endoscopic resection specimen. In case of Low-grade dysplasia, either endoscopic surveillance should be performed every six or 12 months or radiofrequency ablation could be proposed in the yield of prospective studies.

Advances in endoscopic diagnosis and treatment of Barrett's esophagus

Barrett's esophagus (BE) is defined as abnormal specialized columnar metaplasia with intestinalization in place of the normal squamous esophageal epithelium. Gastroesophageal reflux disease is a known risk factor for BE; nonetheless BE is also detected in asymptomatic individuals. Other risk factors for BE include smoking, male gender, age over 50 and obesity. Patients diagnosed with BE (without dysplasia) are recommended to undergo endoscopic surveillance every 3-5 years. Advances in imaging techniques (such as narrow band imaging, autofluorescence imaging and confocal laser endomicroscopy) have the potential to improve the detection of dysplasia and early cancer, thus making surveillance a more cost-effective endeavor. Patients with high grade dysplasia (HGD) and early cancer have a high rate of progression to invasive adenocarcinoma and traditionally these patients were treated with esophagectomy. The rapid advancement of endoscopic therapeutic techniques along with a low risk of complications have made endoscopic therapy an acceptable alternative to an esophagectomy in patients with HGD and early cancer. Several endoscopic treatment techniques such as endoscopic mucosal resection, multipolar electrocoagulation, photodynamic therapy, argon plasma coagulation, cryotherapy, and radiofrequency ablation have been studied for endoscopic treatment.

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.

Endoscopic treatments for Barrett's esophagus: a systematic review of safety and effectiveness compared to esophagectomy

BACKGROUND

Recently, several new endoscopic treatments have been used to treat patients with Barrett's esophagus with high grade dysplasia. This systematic review aimed to determine the safety and effectiveness of these treatments compared with esophagectomy.

METHODS

A comprehensive literature search was undertaken to identify studies of endoscopic treatments for Barrett's esophagus or early stage esophageal cancer. Information from the selected studies was extracted by two independent reviewers. Study quality was assessed and information was tabulated to identify trends or patterns. Results were pooled across studies for each outcome. Safety (occurrence of adverse events) and effectiveness (complete eradication of dysplasia) were compared across different treatments.

RESULTS

The 101 studies that met the selection criteria included 8 endoscopic techniques and esophagectomy; only 12 were comparative studies. The quality of evidence was generally low. Methods and outcomes were inconsistently reported. Protocols, outcomes measured, follow-up times and numbers of treatment sessions varied, making it difficult to calculate pooled estimates.The surgical mortality rate was 1.2%, compared to 0.04% in 2831 patients treated endoscopically (1 death). Adverse events were more severe and frequent with esophagectomy, and included anastomotic leaks (9.4%), wound infections (4.1%) and pulmonary complications (4.1%). Four patients (0.1%) treated endoscopically experienced bleeding requiring transfusions. The stricture rate with esophagectomy (5.3%) was lower than with porfimer sodium photodynamic therapy (18.5%), but higher than aminolevulinic acid (ALA) 60 mg/kg PDT (1.4%). Dysphagia and odynophagia varied in frequency across modalities, with the highest rates reported for multipolar electrocoagulation (MPEC). Photosensitivity, an adverse event that occurs only with photodynamic therapy, was experienced by 26.4% of patients who received porfimer sodium.Some radiofrequency ablation (RFA) or argon plasma coagulation (APC) studies (used in multiple sessions) reported rates of almost 100% for complete eradication of dysplasia. But the study methods and findings were not adequately described. The other studies of endoscopic treatments reported similarly high rates of complete eradication.

CONCLUSIONS

Endoscopic treatments offer safe and effective alternatives to esophagectomy for patients with Barrett's esophagus and high grade dysplasia. Unfortunately, shortcomings in the published studies make it impossible to determine the comparative effectiveness of each of the endoscopic treatments.

The effects of photodynamic therapy in upper-gastrointestinal malignant diseases

Photodynamic therapy (PDT) is a promising new modality that utilizes the combination of a photosensitizing chemical and visible light for the management of various solid malignancies, including gastrointestinal (GI) cancer. PDT has some advantages over chemotherapy in terms of its greater safety and lower toxicity in the treatment of malignant lesions. However, PDT has not been used widely for treating upper GI cancer due to its relatively low cost-effectiveness and anatomical characteristics of the GI system. Nevertheless, PDT may be an effective alternative therapy for early upper-GI cancer patients who are at a high risk of curative surgical resection or systemic chemotherapy. In some clinical studies, PDT for various upper GI cancer showed positiveresults. To improve the efficacy of PDT for upper GI cancer, development of photosensitezer and light delivery system is needed.

New endoscopic and surgical treatment options for early esophageal adenocarcinoma

Although the outcome for advanced stage esophageal cancer is poor, the early detection and treatment of early stage disease is usually associated with a much better outcome. Until recently, esophagectomy has been the treatment of choice in fit patients. However, morbidity is significant, and this has encouraged the development of newer endoscopic treatments that preserve the esophagus. These techniques include ablation and mucosal resection. Promising results are described, and endoscopic methods might provide a reasonable alternative for the treatment of early esophageal cancer. However, follow-up remains short and endoscopic treatment does not deal with potential lymphatic spread. Hence, careful selection is required. Minimally invasive techniques for esophageal resection have also been shown to be feasible, although there is only limited evidence that they reduce postoperative morbidity. Better data are still required to demonstrate improved outcomes from endoscopic treatment and minimally invasive esophagectomy.

Photodynamic therapy for Barrett's esophagus: a systematic review

AIM: To evaluate the efficacy and safety of photodynamic therapy (PDT) for Barrett's esophagus (BE).

METHODS: We searched Cochrane Clinical Trial Register (Issue 4, 2009), Medline or PubMed (1978-2010), EMBase (1978-2010), OVID database (1978-2010), Chinese Biological Medicine database (CBMDisc) (1978-2010), CNKI (1979-2010), Chinese VIP database (1989-2010) and Wanfang database (1978-2010). We also manually searched the bibliographies of retrieved articles and four kinds of important journals to identify randomized controlled trials of PDT for BE. A systematic review was conducted using the method recommended by the Cochrane collaboration.

RESULTS: Ten randomized controlled trials involving 731 patients were included in this systematic review. Three trials reported that PDT could provide safe and effective ablation of low-grade dysplastic epithelium, and proposed that PDT could be used for the treatment of BE at 4-5 h after ALA ingestion and low-dose PDT appeared to be a safe protocol for BE. Three trials showed that PDT in combination with omeprazole was an effective therapy for ablating HGD in patients with BE and in reducing the incidence of esophageal adenocarcinoma. Three trials reported that APC and PDT were equally effective in eradicating Barrett's mucosa, with PDT being the more expensive treatment. However, PDT is more effective in eradicating dysplasia. One trial showed that oral prednisone after PDT did not reduce the incidence of esophageal strictures.

CONCLUSION: PDT is an effective therapy for ablating HGD in patients with BE and in reducing the incidence of esophageal adenocarcinoma. Low-dose PDT is better tolerated in patients with BE.

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.

Radiofrequency ablation for Barrett's esophagus and low-grade dysplasia in combination with an antireflux procedure: a new paradigm

OBJECTIVE

Radiofrequency ablation for Barrett's esophagus in combination with an antireflux procedure has not been widely documented. We report our initial experience with radiofrequency ablation in association with antireflux procedure for Barrett's metaplasia and low-grade dysplasia.

METHODS

A total of 14 patients (10 male and 4 female patients) presented with Barrett's metaplasia (n=11) or low-grade dysplasia (n=3). Median age was 60 years (38-80 years). The severity of Barrett's esophagus was classified by length (in centimeters), appearance (circumferential/noncircumferential), and histology (1, normal; 2, Barrett's metaplasia; and 3, low-grade dysplasia). Radiofrequency ablation was performed with the HALO 360 degrees or 90 degrees systems (BARRX Medical, Sunnyvale, Calif).

RESULTS

Median follow-up was 17 months. The mean number of ablative procedures undertaken was 2.6 (range, 1-6). There was no mortality, but there were 2 perioperative complications after the antireflux procedure (pneumonia, 1; atrial fibrillation, 1). One patient had mild dysphagia requiring a single dilation 2 months after ablation. The mean length of Barrett's esophagus decreased from 6.2 to 1.2 cm after treatment (P=.001). Barrett's grade decreased significantly (P=.003). Before therapy, circumferential Barrett's esophagus was present in 13 patients. At last endoscopy, only 1 patient had circumferential Barrett's esophagus present. The number of radiofrequency ablation treatments was significantly (P < .05) associated with success. All patients receiving 3 or more treatments had complete resolution of Barrett's metaplasia.

CONCLUSIONS

Radiofrequency ablation performed either before or after an antireflux procedure is safe. This approach is effective for reducing or eliminating metaplasia and dysplasia. Long-term studies will be necessary to determine whether this approach can provide durable control of both reflux and Barrett's esophagus.

The role of photodynamic therapy in the esophagus

Photodynamic therapy (PDT) is a drug and device therapy using photosensitizer drugs activated by laser light for mucosal ablation. Porfimer sodium PDT has been used extensively with proven long-term efficacy and durability for the ablation of Barrett esophagus and high-grade dysplasia. and early esophageal adenocarcinoma. However, continued use is hampered by an associated stricture risk and prolonged photosensitivity (4-6 weeks). Promising single-center European studies using other forms of PDT, such as aminolevulinic acid PDT, have not been replicated elsewhere, limiting the widespread use of other forms of PDT. Future use of PDT in esophageal disease depends on the development of improved dosimetry and patient selection to optimize treatment outcomes, while minimizing adverse events and complications.

Complete Barrett's eradication endoscopic mucosal resection: an effective treatment modality for high-grade dysplasia and intramucosal carcinoma--an American single-center experience

OBJECTIVES

Complete Barrett's eradication endoscopic mucosal resection (CBE-EMR) is the endoscopic removal of all Barrett's epithelium with the curative intent of eliminating high-grade dysplasia (HGD)/intramucosal carcinoma (IMC) and reducing the risk of metachronous lesion development. We report our single tertiary referral center's long-term clinical experience using this modality in HGD/IMC management.

METHODS

In this study, we retrospectively reviewed all patients who had CBE-EMR for Barrett's esophagus (BE) with HGD/IMC who had been entered into our center's prospectively collected database. High-definition white-light and narrow-band imaging examinations were used according to the protocol. Staging endoscopic ultrasound was done before CBE-EMR to exclude invasive disease or suspicious lymphadenopathy. High-dose proton pump inhibition was instituted after initial treatment, and Seattle-type surveillance biopsies were performed on follow-up every 6 months once the CBE-EMR procedure was completed.

RESULTS

A total of 49 patients (mean age 67 years, median 65, s.d. 11; 75% men) with histologically confirmed BE and HGD (33), IMC (16), underwent CBE-EMR from August 2003 to August 2008. The mean BE segment length was 3.2 cm (median 2, s.d. 2.2); 26 patients had short-segment BE, and 30 had visible lesions. A total of 106 EMR procedures were performed. On initial EMR, two patients had superficial submucosal carcinoma invasion (sm1) and two had IMC with lymphatic channel invasion. All four patients were referred for esophagectomy, but one opted for continued endoscopic management, without evidence of residual or recurrent carcinoma. A total of 14 patients await completion of EMR (9) or first follow-up endoscopy (5). CBE-EMR therapy was completed in 32 patients by an average of 2.1 sessions (median 2, s.d. 0.9). Surveillance biopsies showed normal squamous epithelium in 31 of 32 (96.9%) patients (mean remission time 22.9 months, median 17, s.d. 16.7, interquartile range 11-38). In all, 10 of 46 patients who continued in the endoscopic protocol had subsquamous Barrett's epithelium on EMR specimens and/or treatment endoscopy biopsies. Overall, 1 of these 10 patients had Barrett's underneath squamous mucosa on most recent surveillance biopsies. CBE-EMR upstaged pre-EMR pathology results in 7 of 49 (14%) of patients and downstaged pathology in 15 of 49 (31%) patients. In all, 18 of 49 (37%) patients developed symptomatic esophageal stenosis after a mean of 24.4 days (median 13.5, s.d. 27.8); all were successfully managed by endoscopic treatment. No perforations or uncontrollable bleeding occurred.

CONCLUSIONS

To our knowledge, this is the largest American single-center experience demonstrating that CBE-EMR with close endoscopic surveillance is an effective treatment modality for BE with HGD/IMC. Although the rate of stenosis development is significant, it is easily treated by endoscopic dilation. Patients considering endoscopic ablation should be counseled appropriately. The role of CBE-EMR in patients with lymphatic invasion or superficial submucosal invasion remains to be defined.

A cost-utility analysis of ablative therapy for Barrett's esophagus

BACKGROUND & AIMS

Recommendations for patients with Barrett's esophagus (BE) include endoscopic surveillance with esophagectomy for early-stage cancer, although new technologies to ablate dysplasia and metaplasia are available. This study compares the cost utility of ablation with that of endoscopic surveillance strategies.

METHODS

A decision analysis model was created to examine a population of patients with BE (mean age 50), with separate analyses for patients with no dysplasia, low-grade dysplasia (LGD), or high-grade dysplasia (HGD). Strategies compared were no endoscopic surveillance; endoscopic surveillance with ablation for incident dysplasia; immediate ablation followed by endoscopic surveillance in all patients or limited to patients in whom metaplasia persisted; and esophagectomy. Ablation modalities modeled included radiofrequency, argon plasma coagulation, multipolar electrocoagulation, and photodynamic therapy.

RESULTS

Endoscopic ablation for patients with HGD could increase life expectancy by 3 quality-adjusted years at an incremental cost of <$6,000 compared with no intervention. Patients with LGD or no dysplasia can also be optimally managed with ablation, but continued surveillance after eradication of metaplasia is expensive. If ablation permanently eradicates >or=28% of LGD or 40% of nondysplastic metaplasia, ablation would be preferred to surveillance.

CONCLUSIONS

Endoscopic ablation could be the preferred strategy for managing patients with BE with HGD. Ablation might also be preferred in subjects with LGD or no dysplasia, but the cost effectiveness depends on the long-term effectiveness of ablation and whether surveillance endoscopy can be discontinued after successful ablation. As further postablation data become available, the optimal management strategy will be clarified.

Monte carlo model of stricture formation in photodynamic therapy of normal pig esophagus

Photodynamic therapy (PDT) is FDA-approved for use in patients with Barrett's esophagus using porfimer sodium (2 mg per kg) and a recommended light dose of 130 J cm(-1) for high grade dysplasia. Despite uniform drug and light doses, the clinical outcome of PDT is variable. A significant number of PDT cases result in esophageal strictures, a side effect related to excessive energy absorption. The purpose of this project was to model esophageal stricture formation with a Monte Carlo simulation. An original multilayer Monte Carlo computer simulation was developed for esophageal PDT. Optical absorption and scattering coefficients were derived for mucosal and muscle layers of normal porcine esophagus. Porfimer sodium was added to each layer by increasing the absorption coefficient by the appropriate amount. A threshold-absorbed light dose was assumed to be required for stricture formation and ablation. The simulation predicted irreversible damage to the mucosa with a 160 J cm(-1) light dose and damage to the muscle layer with an additional 160 J cm(-1) light dose for a tissue porfimer sodium content of 3.5 mg kg(-1). The simulation accurately modeled photodynamic stricture formation in normal pig in vivo esophageal tissue. This preliminary work suggests that the absorbed light threshold for stricture formation may be between 2 and 4 J per gram of tissue.

Treatment options for esophageal cancer

There is considerable controversy over the level of evidence from randomized trials underpinning management decisions for patients presenting with localized cancer of the esophagus and esophago-gastric junction. There is also an optimism that new drugs and new approaches, including response prediction based on sequential (18)FDG-PET scanning following induction chemotherapy, may improve treatments pathways and outcomes. In this review we assess the level of evidence from the major published trials, and discuss new trials and approaches.

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.

Optimal conditions for successful ablation of high-grade dysplasia in Barrett's oesophagus using aminolaevulinic acid photodynamic therapy

Photodynamic therapy (PDT) using 5-aminolaevulinic acid (ALA-PDT) is an attractive alternative to PDT with porfimer sodium for the treatment of high-grade dysplasia (HGD) in Barrett's oesophagus (BO) because of the shorter duration of light photosensitivity and low risk of oesophageal stricture formation. Published results, however, show marked variation in its efficacy, and optimum treatment parameters have not been defined. This study investigated how the dose of ALA and the colour of the illuminating light influenced the biological effect. Twenty-seven patients were enrolled into a randomised controlled trial of red versus green (635 nm or 512 nm) laser light activation for the eradication of HGD with ALA-PDT in Barrett's oesophagus. A further 21 patients were subsequently treated with the most effective regimen. Regular endoscopic follow-up with quadrantic biopsies every 2 cm was performed. The primary outcome measure was eradication of HGD. Patient's receiving ALA at 30 mg/kg relapsed to HGD more than those receiving 60 mg/kg (P = 0.03). Additionally, for those treated with ALA 60 mg/kg, red laser light was more effective than green laser light (P = 0.008). Kaplan-Meier analysis of the 21 patients who were subsequently treated with this optimal regimen demonstrated an eradication rate of 89% for HGD and a cancer-free proportion of 96% at 36 months' follow-up. Using an ALA dose of 60 mg/kg activated by 1,000 J/cm red laser light, we found that ALA-PDT was a highly effective treatment for high-grade dysplasia in Barrett's oesophagus.

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.