High-Energy Laser Therapy of Barrett’s Esophagus: Preliminary Results

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.

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.

Diode laser treatment of Barrett's esophagus: long-term results

Different ablation techniques have been utilized in the treatment of Barrett's esophagus (BE) to reduce the risk of degeneration. Treatment complications, risk of recurrence, and buried intestinal metaplasia (IM) are all major concerns. The effect of diode laser treatment on BE, studied in a group of patients over a long-term period, is presented here. All patients with histology of IM or low-grade dysplasia (LGD) treated with diode laser therapy for BE and followed for at least 24 months were included in the study. Treatment sessions were carried out every 3 months and bioptic follow-up examinations were done yearly. Patients without antireflux surgery received proton pump inhibitors. A total of 20 patients with IM, four of them with LGD, were treated with 161 laser sessions (in mean eight per patient) without complications. Complete, sustained endoscopic and histologic remission was obtained in 13 patients (11/12 with BE ≤ 3 cm and 2/8 with BE >3 cm, p < 0.01) and a mean of 83 ± 27% of the metaplasic tissue was removed in all the patients. All four cases of LGD healed to squamous tissue. No buried metaplasia, recurrences, or disease progressions were reported after a mean follow-up of 6 years and 2 months. Diode laser ablation is a safe and effective method in most cases of short BE, while it is less effective in the long form, requiring a large number of sessions. Long-term results show that the risk of recurrence and of buried intestinal metaplasia underneath neosquamous epithelium is negligible.

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.

Barrett's oesophagus

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

Endoluminal therapy for Barrett's esophagus

This article reviews methods to minimize the complications associated with endoscopic therapy for patients with Barrett's esophagus. To place this discussion in context, the natural history of Barrett's esophagus and the risks associated with progression to dysplasia and invasive carcinoma are reviewed. Operative esophageal resection traditionally is recommended for patients with Barrett's high-grade dysplasia and early carcinoma, and these surgical risks also are reviewed. Finally, all currently approved and commercially available methods for endoscopic ablation and resection of Barrett's disease are categorized according to their application methods of ablation: focal ablation, field ablation, and mucosal resection. The clinical experience with these devices is reviewed with their associated adverse events and complications. Caveats, concerns, and recommendations are discussed to help minimize the complications associated with the use of these important technologies that hold the promise of removing or destroying Barrett's disease to prevent the development of invasive carcinoma.

Laser therapy and surgical treatment in transfusion-dependent patients with upper-gastrointestinal vascular ectasia

We report the results of endoscopic laser therapy on 59 patients with upper gastrointestinal vascular ectasia. After 300 sessions, complications were two nonbleeding and three bleeding ulcers, treated successfully with endoscopic therapy. After treatment, blood transfusions were abolished in 61% and reduced in 22% of the patients, whereas 17% of the patients were nonresponders and 5% died for bleeding. Treatment outcome correlated with endoscopic healing, number of yearly transfusions, and lesions' localization. Patients, who did not respond to laser therapy by the sixth session, showed no improvement afterwards. Four patients with persistence of bleeding despite laser therapy underwent surgery and in three of them, a long-term control of bleeding was obtained. In conclusion, laser therapy was safe and effective; nonetheless, surgical treatment should be considered, after adequate staging, for those patients receiving more than 10 blood units per year or who have undergone more than six laser sessions without improvement.

Use of ethylenediaminetetraacetic acid for in vivo stripping of columnar mucosa: pilot study in an experimental model

BACKGROUND

Barrett's oesophagus is an important clinical problem that can lead to oesophageal adenocarcinoma. A variety of mucosal ablation strategies are now being applied in an attempt to prevent this, although they all can cause complications. Animal experiments that suggest that ethylenediaminetetraacetic acid (EDTA) could be a novel agent for ablation of Barrett's oesophagus are reported in this article.

METHODS

Dark Agouti rats were used in all experiments. To determine the feasibility of using EDTA to strip intestinal type mucosa, segments of the small intestine were exposed in vitro to EDTA at various concentrations with or without agitation. The conditions required for EDTA to strip mucosa from a vascularized loop of small bowel were then optimized in vivo. Cannulated small bowel loops were irrigated with different concentrations of EDTA with or without pulsation of the irrigation solution. The effect of similar treatments on the normal mucosa of the rat oesophagus was then determined. Mucosal healing after EDTA stripping was studied in an isolated small bowel loop survival model.

RESULTS

Ethylenediaminetetraacetic acid with agitation or pulsation resulted in stripping of the intestinal columnar mucosa in vitro and in vivo. The extent was influenced by the concentration of EDTA and duration of exposure. Squamous epithelium was relatively resistant to stripping. In the survival model the small bowel mucosa regenerated without stricture formation.

CONCLUSION

Small bowel columnar mucosa can be removed by EDTA in vivo without stricture formation. A refinement of this approach could be applicable to the ablation of Barrett's oesophagus.

Endoscopic therapy for Barrett's esophagus

With the increase in the rate of esophageal adenocarcinoma in the United States and the Western world matched with the high morbidity and mortality of esophagectomy, there is an increasing need for new and effective techniques to treat and prevent esophageal adenocarcinoma. A wide variety of endoscopic mucosal ablative techniques have been developed for early esophageal neoplasia. However, long-term control of neoplasic risk has not been demonstrated. Most studies show that specialized intestinal metaplasia may persist underneath neo-squamous mucosa, posing a risk for subsequent neoplastic progression. In this article we review current published literature on endoscopic therapies for the management of Barrett's esophagus.

Advances in Barrett's esophagus and esophageal adenocarcinoma

Despite advances in diagnosis and therapy, esophageal adenocarcinoma remains an aggressive and usually lethal tumor. This review focuses on the epidemiology of esophageal adenocarcinoma and its presumed precursor lesion, Barrett's esophagus; the pathogenesis of the cancer; advances in treatment of adenocarcinoma and Barrett's esophagus; and strategies for cancer prevention. Emphasis is placed on recent literature. Although the absolute number of cases of adenocarcinoma in the United States is still small, the incidence of this cancer has increased dramatically in the last 40 years, and adenocarcinoma is now the predominant form of esophageal cancer in this country. Recent evidence suggests that Barrett's esophagus is more prevalent in asymptomatic individuals than previously appreciated. The pathogenesis of Barrett's esophagus is poorly understood. Given that some subjects will have repeated bouts of severe erosive esophagitis and never develop Barrett's esophagus, host factors must play an important role. The utility of neoadjuvant radiation and chemotherapy in those with adenocarcinoma, although they are widely practiced, is not of clear benefit, and some authorities recommend against it. Ablative therapies, as well as endoscopic mucosal resection, hold promise for those with superficial cancer or high-grade dysplasia. Most series using these modalities feature relatively short follow-up, and longer-term data will be necessary to better describe the effects of these therapies. The value of chemoprevention in subjects with dysplastic Barrett's esophagus by use of cyclooxygenase 2 inhibitors, nonsteroidal anti-inflammatory drugs, or proton pump inhibitors is unknown. Similarly, although endoscopic screening is widely practiced, its value in patients with chronic gastroesophageal reflux disease symptoms is of unproven value, and recommending bodies are divided as to its practice.