Endoscopic therapy for Barrett's oesophagus

An endoscopic approach providing near-infrared laser-induced coagulation with accurate depth limits

This article investigates an endoscopic approach that utilizes negative pressure to achieve laser-induced thermal coagulation limited to the esophageal wall's mucosal and superficial submucosal layers. The study was built upon a series of studies combining numerical simulation based on the Monte-Carlo technique and ex vivo porcine tissue experiments, including apparatus design and histology analysis. An endoscopy apparatus was developed using 3D printing to validate the tissue stretching-based approach. A fiber-pigtailed diode was used as the near-infrared source, emitting 208.8 W/cm2 laser irradiance at 1.5 μm. Simulation results suggested that the approach successfully created a local heat well to prevent residual thermal effects (>65°C) from penetrating the deeper submucosal layer. Histology analysis of ex vivo tissues showed that at a fluence of 5.22 kJ/cm2, the depth of thermal coagulation was reduced by half compared to the control. With further preclinical studies, including endoscopy apparatus design, the approach can be applied to the larger esophageal surface.

Superficial photothermal laser ablation of ex vivo sheep esophagus using a cone-shaped optical fiber tip

Superficial photothermal laser ablation (SPLA) may be useful as a therapeutic approach producing a depth of injury that is sufficient to eliminate mucosal lesion but not deep enough to induce thermal effects in deeper tissue layers. The purpose of this preliminary study is twofold: (a) to describe design steps of a fiber probe capable of delivering a tightly focused laser beam, including Monte-Carlo-based simulations, and (b) to complete the initial testing of the probe in a sheep esophagus model, ex vivo. The cone-shaped (tapered) fiber tip was obtained by chemical etching of the optical fiber. A 1505 nm diode laser providing power up to 500 mW was operated in continuous wave. The successful SPLA of the sheep mucosa layer was demonstrated for various speed-power combinations, including 300 mW laser power at a surface scanning rate of 0.5 mm/s and 450 mW laser power at a surface scanning rate of 2.0 mm/s. Upon further development, this probe may be useful for endoscopic photothermal laser ablation of the mucosa layer using relatively low laser power.

Structural markers observed with endoscopic 3-dimensional optical coherence tomography correlating with Barrett's esophagus radiofrequency ablation treatment response (with videos)

BACKGROUND

Radiofrequency ablation (RFA) is effective for treating Barrett's esophagus (BE) but often involves multiple endoscopy sessions over several months to achieve complete response.

OBJECTIVE

Identify structural markers that correlate with treatment response by using 3-dimensional (3-D) optical coherence tomography (OCT; 3-D OCT).

DESIGN

Cross-sectional.

SETTING

Single teaching hospital.

PATIENTS

Thirty-three patients, 32 male and 1 female, with short-segment (<3 cm) BE undergoing RFA treatment.

INTERVENTION

Patients were treated with focal RFA, and 3-D OCT was performed at the gastroesophageal junction before and immediately after the RFA treatment. Patients were re-examined with standard endoscopy 6 to 8 weeks later and had biopsies to rule out BE if not visibly evident.

MAIN OUTCOME MEASUREMENTS

The thickness of BE epithelium before RFA and the presence of residual gland-like structures immediately after RFA were determined by using 3-D OCT. The presence of BE at follow-up was assessed endoscopically.

RESULTS

BE mucosa was significantly thinner in patients who achieved complete eradication of intestinal metaplasia than in patients who did not achieve complete eradication of intestinal metaplasia at follow-up (257 ± 60 μm vs 403 ± 86 μm; P < .0001). A threshold thickness of 333 μm derived from receiver operating characteristic curves corresponded to a 92.3% sensitivity, 85% specificity, and 87.9% accuracy in predicting the presence of BE at follow-up. The presence of OCT-visible glands immediately after RFA also correlated with the presence of residual BE at follow-up (83.3% sensitivity, 95% specificity, 90.6% accuracy).

LIMITATIONS

Single center, cross-sectional study in which only patients with short-segment BE were examined.

CONCLUSION

Three-dimensional OCT assessment of BE thickness and residual glands during RFA sessions correlated with treatment response. Three-dimensional OCT may predict responses to RFA or aid in making real-time RFA retreatment decisions in the future.

Comparison of Tissue Architectural Changes between Radiofrequency Ablation and Cryospray Ablation in Barrett's Esophagus Using Endoscopic Three-Dimensional Optical Coherence Tomography

Two main nonsurgical endoscopic approaches for ablating dysplastic and early cancer lesions in the esophagus have gained popularity, namely, radiofrequency ablation (RFA) and cryospray ablation (CSA). We report a uniquely suited endoscopic and near-microscopic imaging modality, three-dimensional (3D) optical coherence tomography (OCT), to assess and compare the esophagus immediately after RFA and CSA. The maximum depths of architectural changes were measured and compared between the two treatment groups. RFA was observed to induce 230~260 μm depth of architectural changes after each set of ablations over a particular region, while CSA was observed to induce edema-like spongiform changes to ~640 μm depth within the ablated field. The ability to obtain micron-scale depth-resolved images of tissue structural changes following different ablation therapies makes 3D-OCT an ideal tool to assess treatment efficacy. Such information could be potentially used to provide real-time feedback for treatment dosing and to identify regions that need further retreatment.

The effects of laparoscopic Nissen fundoplication on Barrett's esophagus: long-term results

OBJECTIVE

The aim of our study was to conduct a retrospective investigation of the efficacy of laparoscopic Nissen fundoplication in patients with Barrett's esophagus.

MATERIAL AND METHODS

A total of 78 patients with Barrett's esophagus underwent surgery. Patients were divided into three groups on the basis of the preoperative endoscopic biopsies: a non-intestinal group (n = 63) with fundic or cardiac metaplasia, an intestinal group (n = 18) with intestinal metaplasia, and a dysplastic group (n = 7) with low-grade dysplasia. Clinical follow-up was available in the case of 64 patients at a mean of 42 ± 16.9 months after surgery.

RESULTS

Check-up examination revealed total regression of Barrett's metaplasia in 10 patients. Partial regression was seen in 9 cases, no further progression in 34 patients, and progression into cardiac or intestinal metaplasia in 11 patients. No cases of dysplastic or malignant transformation were registered. Where we observed the regression of BE, among the postoperative functional examinations results of manometry (pressure of lower esophageal sphincter) and pH-metry were significantly better compared with those groups where no changes occurred in BE, or progression of BE was found. Discussion. Our results highlight the importance of the cases of fundic and cardiac metaplasia, which can also transform into intestinal metaplasia.

CONCLUSIONS

Antireflux surgery can appropriately control the reflux disease in a majority of the patients who had unsuccessful medical treatment, and it may inhibit the progression and induce the regression of Barrett's metaplasia in a significant proportion of these patients.

A systematic review of the evidence for radiofrequency ablation for Barrett's esophagus

BACKGROUND

Radiofrequency ablation with the HALO system is a new option for the treatment of patients with Barrett's esophagus. This systematic review summarizes the results of all relevant publications on this topic to answer patient-relevant clinical questions and to evaluate the potential benefit and harm of this new therapy.

METHODS

A systematic literature search of MEDLINE and CENTRAL up to May 2009 was performed. To identify the relevant literature, references were evaluated by two reviewers independently. The inclusion criteria for the review required that studies investigated patients with Barrett's esophagus, used radiofrequency ablation as the intervention, and had a minimum follow-up period of 12 months.

RESULTS

A total of nine relevant observational studies (involving 429 patients) were identified. Complete eradication of Barrett's esophagus dysplasia and metaplasia was achieved respectively for 71-100% and for 46-100% of the patients. Only six cases of stenosis and one case of buried intestinal metaplasia were reported among all the patients. Only a few mild adverse events were reported.

CONCLUSIONS

Based on the evidence of observational studies, the summary of the current data suggests that radiofrequency ablation with the HALO system could be a promising method associated with a low complication rate, low risk of stricture formations, and a minor probability of buried glands. To evaluate the potential benefit at a higher level of evidence, randomized controlled trials (RCTs) involving a direct comparison with other more established endoscopic methods such as photodynamic therapy are necessary.

A systematic review of the evidence for radiofrequency ablation for Barrett's esophagus

BACKGROUND

Radiofrequency ablation with the HALO system is a new option for the treatment of patients with Barrett's esophagus. This systematic review summarizes the results of all relevant publications on this topic to answer patient-relevant clinical questions and to evaluate the potential benefit and harm of this new therapy.

METHODS

A systematic literature search of MEDLINE and CENTRAL up to May 2009 was performed. To identify the relevant literature, references were evaluated by two reviewers independently. The inclusion criteria for the review required that studies investigated patients with Barrett's esophagus, used radiofrequency ablation as the intervention, and had a minimum follow-up period of 12 months.

RESULTS

A total of nine relevant observational studies (involving 429 patients) were identified. Complete eradication of Barrett's esophagus dysplasia and metaplasia was achieved respectively for 71-100% and for 46-100% of the patients. Only six cases of stenosis and one case of buried intestinal metaplasia were reported among all the patients. Only a few mild adverse events were reported.

CONCLUSIONS

Based on the evidence of observational studies, the summary of the current data suggests that radiofrequency ablation with the HALO system could be a promising method associated with a low complication rate, low risk of stricture formations, and a minor probability of buried glands. To evaluate the potential benefit at a higher level of evidence, randomized controlled trials (RCTs) involving a direct comparison with other more established endoscopic methods such as photodynamic therapy are necessary.

[Endoscopic argon plasma thermo-coagulation of Barrett's esophagus using different powers: histopathological and post procedure symptons analysis]

OBJECTIVE

To establish the ideal power to be employed in order to get the effective ablation and the lowest rate of symptoms at argon plasma thermocoagulation in Barrett's esophagus (BE).

METHODS

Twenty-eight asymptomatic patients with BE, were randomly divided in two groups of different ablation powers, 50W or 70W. After endoscopic ablation and biopsies from the treated area for histological analyses, symptoms were evaluated through a questionnaire answered by phone.

RESULTS

Thirteen patients without specialized columnar metaplasia were excluded and the remaining fifteen patients, seven men (46,7%) and eight women (53,3%), with an average age of 53 years +10,4, composed the two groups: 10 patients at the 70W power and 5 at the 50W power group. There was no significant difference between the groups regarding age, BE extent, percentage of coagulated esophageal circumference and the duration of symptoms. Pain was the most important symptom, with a mean duration of 10,3 + 9,7 days. When power was compared to symptoms, although not statistically significant, a moderate negative correlation was noted. Endoscopic biopsies showed ablation restricted to the mucosa's superficial layer in 40% of the cases in the lower power group, and only 10% in the higher power group, although deeper layers of the mucosa were compromised. There were no statistical significant differences when comparing the different powers to the penetration through the mucosa's layers and the symptoms.

CONCLUSION

There are evidences that the 70W potency argon plasma coagulation for BE leads to a lower incidence of residual specialized columnar metaplasia under the new scamous epithelium.

Barrett's esophagus and the increasing role of endoluminal therapy

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

Endoscopic therapy of dysplasia and early-stage cancers of the esophagus

Endoscopic treatments have become a viable alternative for some patients with early-stage esophageal neoplasia. Although esophagectomy remains the standard of care for high-grade dysplasia and superficial cancers, surgical morbidity and mortality may deter patients who are medically unfit or reluctant to undergo surgery. Photodynamic therapy (PDT) and endoscopic mucosal resection (EMR) are the best-studied nonsurgical approaches at present. PDT has been reported to eradicate high-grade dysplasia (HGD) and early Barrett's cancers at rates ranging from 75% to 100% and 17% to 100%, respectively, and a recent randomized controlled trial confirmed that PDT may prevent progression of HGD to cancer. Complete remission rates greater than 90% have also been reported with EMR and other mucosa-ablating interventions, although recurrence rates necessitate close endoscopic surveillance and retreatment in some patients. In addition to PDT and EMR, several emerging endoscopic treatment options for superficial esophageal neoplasia may provide attractive alternatives to surgery.

Emerging aspects of oesophageal and gastro-oesophageal junction cancer histopathology - an update for the surgical oncologist

Adenocarcinoma of the oesophagus and gastro-oesophageal junction are rapidly increasing in incidence and have a well described sequence of carcinogenesis: the Barrett's metaplasia-dysplasia-adenocarcinoma sequence. During recent years there have been changes in the knowledge surrounding disease progression, cancer management and histopathology specimen reporting. Tumours around the gastro-oesophageal junction (GOJ) pose several specific challenges. Numerous difficulties arise when the existing TNM staging systems for gastric and oesophageal cancers are applied to GOJ tumours. The issues facing the current TNM staging and GOJ tumour classification systems are reviewed in this article. Recent evidence regarding the importance of several histopathologically derived prognostic factors, such as circumferential resection margin status and lymph node metastases, have implications for specimen reporting. With the rising use of multimodal treatments for oesophageal cancer it is important that the response of the tumour to this therapy is carefully documented pathologically. In addition, several controversial and novel areas such as endoscopic mucosal resection, lymph node micrometastases and the sentinel node concept are being studied. We aim to review these aspects, with special relevance to oesophageal and gastro-oesophageal cancer specimen reporting, to update the surgical oncologist with an interest in upper gastrointestinal cancer.

Surgical treatment of superficial esophageal cancer

OBJECTIVE

The worldwide incidence of superficial esophageal cancer (SEC) is increasing. The aim of this study is to review the systematic surgical outcomes of esophagectomy for SEC.

DATA SOURCES

Only manuscripts written in English and written between 1980 and 2003 were selected from MEDLINE. The keywords consisting of superficial esophageal cancer, early esophageal cancer, and early stage or superficial stage or stage I in esophageal cancer were searched.

STUDY SELECTION

There were no exclusion criteria for published information relevant to the topics. The most representative articles were selected when there were several articles from the same institution. Case reports were excluded. DATA EXTRACTIONS: Thirty-two manuscripts were finally collected from MEDLINE and eight articles were also added from reference lists of the pertinent literatures. In evaluating the statistical analysis of the complications of the reported literature, collective method was used.

DATA SYNTHESIS

The collected information was organized.

CONCLUSIONS

The conclusions drawn from those articles showed that the overall prevalence of SEC accounted around 10% and increased to 25% in the 2000s. The overall incidence of lymph node metastasis of SEC was about 25% and its incidences in mucosal and submucosal cancer were 5 and 35%, respectively. The percentage of the cases of squamous cell carcinoma (SCC) vs adenocarcinoma (AC) widely varied depending on the geographic locations reported; most SCC cases were from the Asian countries and most AC cases were from the European countries. Clinical significance of multimodal treatment for SEC has dramatically developed in the recent era and could provide various potential therapeutic options for SEC. These concepts make it possible to individualize surgical management of SEC as part of various multimodal treatments. The operative approaches for SEC varied from minimally invasive thoracoscopic esophagectomy, limited transabdominal distal esophagectomy, conventional transthoracic esophagectomy, transhiatal esophagectomy without thoracotomy, en bloc esophagectomy, and to extended esophagectomy with a complete three-field lymph node dissection. A 5-year overall survival rate of SEC after esophagectomy was good (46 to 83%) to excellent (71 and 100%) for mucosal SEC, but far from satisfactory (33 and 78%) for submucosal SEC. Early diagnosis, development of multimodal treatment, standardization of the surgical procedure including routine lymph node dissection, and improved perioperative management of patients have led to a better survival for patients with SEC.

Light dosimetry measurements during ALA-PDT of Barrett's oesophagus

A fibre optic probe and compact light detection system has been used to monitor the fluence-rate at the tissue surface during 5-aminolaevulinic acid based photodynamic therapy (PDT) of Barrett's oesophagous. The contributions from three specific wavelengths were recorded, corresponding to the combination of therapeutic laser light and fluorescence emission from protoporphyrin IX (635nm), the fluorescence from an oxidation product of the photosensitiser (670nm), and the protoporphyrin IX fluorescence alone (705nm). We have found that light scattering results in an enhancement of the therapeutic fluence-rate, and hence light dose, by approximately 70%. At the onset of therapy the fluorescence provides a 10% contribution to the overall fluence-rate at 635nm. The dynamics of photosensitiser bleaching could be extracted from the depletion in light signals. By defining a bleaching dose as the 635nm light fluence delivered over the period during which the photosensitiser fluorescence decays to 1/e(3) of its initial value, we find that the average ratio of bleaching to total dose is 33%. Further, the fluorescence contributes approximately 5% of the bleaching light dose. These results suggest that the prescribed period of therapeutic light exposure may be reduced with no loss in clinical efficacy, but with a consequent improvement in patient tolerance to this therapy.