High power setting argon plasma coagulation for the eradication of Barrett's esophagus

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.

Visible endoscopic and histologic changes in the cardia, before and after complete Barrett's esophagus ablation

BACKGROUND

Adverse events associated with the thermal ablation of Barrett's esophagus (BE) include the generation of gastric mucosa buried beneath the neosquamous regrowth, and unrecognized development and growth of adenocarcinomas. No reports exist regarding the endoscopic appearance and histology of the cardia before and after BE ablation. The aim of our study was to assess the relative frequency of the occurrence of visible endoscopic and histologic changes in the cardia, before and after complete BE ablation.

METHODS

A subset analysis of patients with uncomplicated BE, BE with dysplasia, or early carcinoma, who had been enrolled into one of 4 ongoing prospective studies of mucosal ablation, was examined. Eighty-two patients were identified who entered a BE ablation study, with 75 of these completing BE mucosal ablation. Cardia biopsy specimens were taken in all patients before ablation and serially after BE ablation. Cardia histology was graded by using the modified Sydney System for gastritis.

RESULTS

Before ablation, cardia nodules were noted in 3, cardia intestinal metaplasia (IM) in 7 (8.5%), and none harbored cardia dysplasia. Postablation surveillance ranged from 3 to 75 months (mean 31.1 months [19.5]). Six subjects (8%) developed cardia nodules during surveillance; cardia IM was found in 21(28%), with 17 of these being a new finding (incidence of 25%). Cardia low-grade dysplasia incidence was 1.3% and high-grade dysplasia was 4% after BE ablation.

CONCLUSIONS

The pathophysiology of the abnormal cardia histology and the endoscopic lesions (nodules) is unclear, but endoscopic surveillance of not only the neosquamous epithelium but also the cardia should be considered after ablation, especially in those high-grade dysplasia and early adenocarcinoma BE patients.

Endoscopic ablation of Barrett’s esophagus using high power setting argon plasma coagulation: A prospective study

AIM: This prospective study evaluated the effectiveness of 90 W argon plasma coagulation (APC) for the ablation of Barrett’s esophagus (BE) that is considered to be the main risk factor for the development of esophageal adenocarcinoma.

METHODS: The results from 25 patients, observed at the First Department of General Surgery, University of Verona, Italy, from October 2000 to October 2003, who underwent APC for histologically proven BE were prospectively analyzed.

RESULTS: The ablation treatment was completed in all the patients but one (96%). The mean number of APC sessions needed to complete ablation was 1.6 (total number: 40). The eradication was obtained in the majority of cases by one session only (60%), two sessions were required in 24% of the cases and three or more in 16%. About 43% of the sessions were complicated. Retrosternal pain (22.5%) and fever (17.5%) were the most frequent symptoms. Only one major complication occurred, it was an hemorrhage due to ulcer formation on the treated esophagus that required urgent endoscopic sclerosis and admission. The follow-up was accomplished in all the patients with a mean period of 26.3 mo and 20 patients (84%) with a follow-up period longer than 24 mo. Only one patient showed a relapse of metaplastic mucosa 12 mo after the completion of ablation. The patient was hence re-treated and now is free from recurrence 33 mo later.

CONCLUSION: High power setting (90 W) APC showed to be safe and effective. The effects persist at a mean follow-up period of two years with a comparable cost in term of complications with respect to standard power settings. Further studies with greater number of patients are required to confirm these results and to assess if ablation reduces the incidence of malignant progression.

Present status of photodynamic therapy for high-grade dysplasia in Barrett's esophagus

GOALS

Review recent developments in Barrett's dysplasia including regulatory approval of porfimer sodium photodynamic therapy.

BACKGROUND

Barrett's esophagus is thought to be the result of long-standing gastroesophageal reflux disease and is known to be the most important risk factor for the development of esophageal adenocarcinoma. The natural history of Barrett's esophagus is not well known, but the annual incidence of invasive adenocarcinoma is estimated to be 0.5% (reported range, 0.2%-2.0%). This represents an increased risk for esophageal cancer of 30 to 60 times higher than normal subjects. As for colorectal cancer, malignant degeneration is Barrett's esophagus is thought to occur through a continuum of histologic stages: metaplasia, dysplasia and neoplasia. Barrett's high-grade dysplasia (formerly referred to as carcinoma in situ) is the histologic stage of disease that immediately precedes the development of invasive carcinoma.

CONCLUSIONS

Previously, Barrett's high-grade dysplasia patients were routinely referred for esophageal resection surgery based upon the assumption of inevitable progression to cancer, the high rate of undiagnosed synchronous cancers, and few treatment alternatives. Important developments in Barrett's high-grade dysplasia include recent publications regarding the natural history of Barrett's high-grade dysplasia and the regulatory approval for endoscopic ablation therapy using porfimer sodium photodynamic therapy (Photofrin PDT).

Long-term follow-up after complete ablation of Barrett’s esophagus with argon plasma coagulation

AIM: To report the long-term outcome of patients after complete ablation of non-neoplastic Barrett’s esophagus (BE) with respect to BE relapse and development of intraepithelial neoplasia or esophageal adenocarcinoma.

METHODS: In 70 patients with histologically proven non-neoplastic BE, complete BE ablation was achieved by argon plasma coagulation (APC) and high-dose proton pump inhibitor therapy (120 mg omeprazole daily). Sixty-six patients (94.4%) underwent further surveillance endoscopy. At each surveillance endoscopy four-quadrant biopsies were taken from the neo-squamous epithelium at 2 cm intervals depending on the pre-treatment length of BE mucosa beginning at the neo-Z-line, and from any endoscopically suspicious lesion.

RESULTS: The median follow-up of 66 patients was 51 mo (range 9-85 mo) giving a total of 280.5 patient years. A mean of 6 biopsies were taken during surveillance endoscopies. In 13 patients (19.7%) tongues or islands suspicious for BE were found during endoscopy. In 8 of these patients (12.1%) non-neoplastic BE relapse was confirmed histologically giving a histological relapse rate of 3% per year. In none of the patients, intraepithelial neoplasia nor an esophageal adenocarcinoma was detected. Logistic regression analysis identified endoscopic detection of islands or tongues as the only positive predictor of BE relapse (P = 0.0004).

CONCLUSION: The long-term relapse rate of non-neoplastic BE following complete ablation with high-power APC is low (3% per year).

Randomized trial of argon plasma coagulation vs. multipolar electrocoagulation for ablation of Barrett's esophagus

BACKGROUND

Endoscopic ablation of Barrett's esophagus has been described in which various thermocoagulation modalities are used in combination with a high dose of a proton pump inhibitor. No randomized comparison of ablation strategies has been published.

METHODS

Referred patients were screened to identify those with Barrett's esophagus 2 to 7 cm in length, without high-grade dysplasia or cancer. Included patients received pantoprazole (40 mg twice a day), followed by randomization to treatment with argon plasma coagulation (APC) or multipolar electrocoagulation (MPEC). The primary outcome measure was the number of treatment sessions required for endoscopic ablation.

RESULTS

Of 235 patients screened, 52 were randomized. The mean length of Barrett's esophagus was 3.1 cm in the MPEC group vs. 4.0 cm in the APC group (p = 0.03). Otherwise, the treatment groups were similar with regard to baseline characteristics. The mean number of treatment sessions required for endoscopic ablation was 2.9 for MPEC vs. 3.8 for APC (p = 0.04) in an intention-to-treat analysis (p = 0.249, after adjustment for the difference in length of Barrett's esophagus). The proportion of patients in which ablation was endoscopically achieved proximal to the gastroesophageal junction was 88% for the MPEC group vs. 81% for the APC group (p = 0.68) and histologically achieved in 81% for MPEC vs. 65% for APC (p = 0.21). The mean time required for the first treatment session was 6 minutes with MPEC vs. 10 minutes with APC (p = 0.01) in per protocol analysis. There was no serious adverse event, but transient moderate to severe upper-GI symptoms occurred after MPEC in 8% vs. 13% after APC (p = 0.64). Conclusions Although there were no statistically significant differences, ablation of Barrett's esophagus with pantoprazole and MPEC required numerically fewer treatment sessions, and endoscopic and histologic ablation was achieved in a greater proportion of patients compared with treatment with pantoprazole and APC.

Molecular evaluation of ablative therapy of Barrett's oesophagus

Barrett's oesophagus is a major risk factor for developing oesophageal adenocarcinoma. Ablation by argon plasma coagulation (APC) and photodynamic therapy (PDT) is currently under investigation for the removal of metaplastic and dysplastic Barrett's oesophagus. This study examined the effect of ablative therapy on Barrett's oesophagus at cell-cycle and genetic levels. The premalignant potential of residual or recurring Barrett's oesophagus was assessed by p53 immunohistochemistry, Ki67-related proliferative capacity, and DNA ploidy status (ie an abnormal chromosome 1 number) as measured by interphase in situ hybridization. Twenty-nine patients with Barrett's oesophagus (23 male and 6 female, mean age 58 years, mean length of Barrett's oesophagus 4 cm) were treated with APC or PDT. Intestinal metaplasia without dysplasia was present in 16 patients, low-grade dysplasia in five, and high-grade dysplasia in eight patients. Biopsy samples were obtained at regular intervals (mean follow-up 20 months, range 6-36 months). One month after the first ablation, Barrett's oesophagus was no longer identified, either endoscopically or histologically, in nine patients (32%). At this time point, significant down-grading was achieved for abnormal chromosome 1 numbers (p = 0.020) and Ki67-defined proliferation (p = 0.002). Patients with residual Barrett's oesophagus were additionally treated with APC, resulting in the elimination of Barrett's oesophagus in 76% of all patients. However, at the last follow-up endoscopy, metaplasia without dysplasia was still present in five patients, and low- and high-grade dysplasia were each present in one patient. An abnormal chromosome 1 number and p53 protein overexpression were detected only in the high-grade dysplastic lesion, but increased proliferation was still present in the majority of these persisting cases. Although endoscopic removal of Barrett's oesophagus by ablative therapies is possible in the majority of patients, histologically complete elimination cannot be achieved in all cases. Persistent Barrett's oesophagus may still harbour molecular aberrations and must therefore be considered still to be at risk of progression to adenocarcinoma.

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

BACKGROUND

Barrett's oesophagus is the major risk factor for oesophageal adenocarcinoma. 5-Aminlevulinic acid-induced photodynamic therapy and argon plasma coagulation have been shown to be effective for ablating Barrett's oesophagus, but a comparative trial of these two modalities has not been reported.

AIMS

To compare photodynamic therapy and argon plasma coagulation for the ablation of Barrett's oesophagus.

METHODS

A total of 68 patients (54 male, 14 female; median age 61) with Barrett's oesophagus were randomized to photodynamic therapy (n = 34) or argon plasma coagulation (n = 34). Photodynamic therapy was performed using 5-aminlevulinic acid (30 mg/kg) and red light. Argon plasma coagulation was administered at a power setting of 65 W. Multiple treatment sessions were performed, with follow-up to 24 months.

RESULTS

All patients showed a macroscopic reduction in the area of Barrett's oesophagus. This was greatest in the argon plasma coagulation group with 33 of 34 (97%) ablated, compared with 17 of 34 (50%) in the photodynamic therapy group; in the remainder, there was a reduction in the length of Barrett's oesophagus (median 50%, range: 5-90). Buried glands were found in 24% of photodynamic therapy patients, and in 21% of argon plasma coagulation patients. The median follow-up is 12 months (range: 6-24).

CONCLUSIONS

Photodynamic therapy and argon plasma coagulation are both effective for ablating Barrett's oesophagus. Argon plasma coagulation appears more effective than photodynamic therapy, but the impact of both on carcinoma development requires larger studies with long-term follow-up.

Endoscopic ablation of Barrett's esophagus using argon plasma coagulation: a prospective study after fundoplication

The aim of the prospective clinical study presented here is to test the effectiveness of a multimode approach consisting of argon plasma coagulation combined with laparoscopic fundoplication in the management of Barrett's esophagus. Argon plasma coagulation was performed in 19 patients with Barrett's esophagus who had previously undergone surgical antireflux treatment. The mean follow-up time was 17 months, ranging between 6 and 27 months. Squamous epithelium was completely restored in all patients. In 68.4% of cases two sessions were required. The most frequent complications were chest discomfort and retrosternal pain. In 11 patients the symptoms lasted 3 days and in six cases persisted for a longer period, requiring analgesic medication. Short-term dysphagia and odynophagia were observed in four patients.

Use of argon plasma coagulation in endourology: in vitro experiments

OBJECTIVES

To investigate different parameters influencing argon plasma coagulation (APC) in a fluid medium with regard to endourologic procedures. APC is a novel therapeutic modality of noncontact electrocoagulation that applies high-frequency current by way of ionized argon gas. Recent modifications for endoscopic application of APC have helped to establish new indication in various surgical fields.

METHODS

Standardized experiments using an endoscopic APC device were performed on fresh bovine skeletal muscle in different fluid media. The effects of the power setting, gas flow rates, and treatment duration on the coagulation zones and tissue ablation were evaluated.

RESULTS

The coagulation zones were remarkably uniform. The depths of coagulation increased significantly with augmented power settings and APC duration but were not dependent on gas flow rates. Likewise, tissue removal increased with greater power and longer application times but was not affected by flow rates. Tissue ablation in general was moderate. Different fluid media generated varying performances.

CONCLUSIONS

Using a laboratory model, we demonstrated that APC performed in a fluid medium is feasible. The power setting, treatment duration, and different fluid media were interdependent factors affecting the performance of APC in a fluid milieu. However, before application of APC in endourologic procedures in humans, additional studies concerning safety issues are mandatory.

Prospective randomized controlled trial of argon plasma coagulation ablation vs. endoscopic surveillance of patients with Barrett's esophagus after antireflux surgery

BACKGROUND

Argon plasma coagulation is one of several techniques used to ablate Barrett's esophagus. This study assessed the efficacy and safety of argon plasma coagulation in the ablation of Barrett's esophagus in patients who have undergone antireflux surgery.

METHODS

A total of 40 patients with Barrett's esophagus who had undergone a fundoplication were entered into a prospective, randomized, unblinded study comparing argon plasma coagulation with endoscopic surveillance. Treatment was repeated until either no Barrett's epithelium remained or a maximum of 6 treatment sessions.

RESULTS

One month after the final treatment, complete ablation was achieved in 12 patients. In the remaining 8, a reduction of over 95% was observed. One patient died at 9 months of an unrelated cause. At 1 year, one patient with residual Barrett's epithelium regressed completely, while relapse of Barrett's esophagus was seen in another because of fundoplication failure. Buried glands were observed in 35% patients at 1 month, but only 5% at 1 year. Dysplasia was never seen. In the surveillance group, partial regression was observed in 11 patients, and, in 3 with short-segment Barrett's esophagus, regression was complete. The length of Barrett's esophagus increased in two patients. Two had low-grade dysplasia initially, but this was not evident at 1 year. Overall, complete ablation was achieved in 12 of 19 (63%) patients in the ablation group and 3 of 20 (15%) in the surveillance group (p<0.01).

CONCLUSIONS

Argon plasma coagulation of Barrett's esophagus is safe and effective. The effects are durable, and buried glands may resolve with time. Long-term follow-up is required to assess the impact of argon plasma coagulation on cancer risk.

Prevention of adenocarcinoma by reversing Barrett's esophagus with mucosal ablation

The ultimate goal of therapy in patients with Barrett's esophagus (BE) is to reduce the risk of developing adenocarcinoma of the esophagus. Neither pharmacologic nor surgical therapy has been documented to reduce this risk. There is preliminary evidence that many forms of mucosal ablation combined with acid reduction therapy result in restitution of normal squamous epithelium in patients with BE. Acid reduction can be accomplished with high-dose proton pump inhibitor therapy or antireflux surgery. Endoscopic ablation can be accomplished with photodynamic therapy, laser, multipolar electrocoagulation, a heater probe, and argon plasma coagulation. These techniques require further study so the complication rates can be compared. The success of reversing BE must be evaluated in a standard way utilizing large-capacity biopsy forceps through a therapeutic endoscope. Ideally, patients at high risk of developing adenocarcinoma of the esophagus can be treated with ablation therapy and followed to document a reduction in the development of adenocarcinoma of the esophagus. A validated biomarker would help select high risk patients appropriate for reversal therapy. Currently, patients who are at prohibitive risk for surgery or who refuse surgery are candidates for combination therapy including mucosal ablation to reverse their BE. This therapy offers the promise of less morbidity and greater quality of life than resection.

Argon plasma coagulation (APC) for endo-urological procedures: ex-vivo evaluations of hemostatic properties

OBJECTIVES

Argon plasma coagulation (APC) is an innovative therapeutic modality of non-contact electrocoagulation, which applies high-frequency current via ionized argon plasma. After several years of successful use in open surgery, endoscopic techniques have been established in various surgical fields. The aim of this study was to evaluate the hemostatic properties of this technique in a fluid medium with regard to endourological procedures.

METHODS

Isolated blood-perfused porcine kidneys were used to determine hemostatic efficacy of APC following TURP-like tissue ablation with a conventional loop electrode, compared to standard electrocoagulation with a ball electrode after tissue resection. Blood loss was quantified, specimens were evaluated histologically for coagulation zones.

RESULTS

APC following tissue resection significantly (p<0.001) reduced bleeding compared to conventional contact electrocoagulation subsequent to tissue resection for an ablation volume of 4 cm(3) of perfused kidney tissue (2.1 ml/min vs. 5.6 ml/min). The depths of the coagulation zones were significantly larger (2.4 mm vs. 0.8 mm) and remarkably uniform for the groups treated with APC following tissue resection.

CONCLUSIONS

APC performed in a fluid medium is feasible. APC following conventional TURP-like tissue resection creates significantly better hemostasis compared to standard contact coagulation after tissue resection. These findings justify further investigations to elucidate the value of APC in endourological procedures.

Argon plasma coagulation in Barrett's esophagus

Despite the availability of many clinical trials, there is no evidence that APC has any role in the management of Barrett's esophagus. Ablation therapy is not indicated for nondysplastic Barrett's esophagus (and this is true, whatever the technique used), and it should not be performed outside of a carefully designed and approved clinical trial. Indeed, these patients have a low risk of cancer, and there is no evidence that Barrett's esophagus ablation will be of any benefit for these patients. In some cases, APC could be of some help, especially for treating short segments of dysplastic Barrett's esophagus. In this field, however, it competes with the growing indication of mucosectomy, which clearly offers advantages in terms of treatment's quality control assessment.

Barrett's esophagus: an update

Barrett's esophagus (BE) is a complication observed in a small subset of patients with chronic gastroesophageal reflux. It is characterized by the presence of intestinal-type goblet cells in biopsies from the lower esophagus. The prevalence of BE increases with age, affecting 1% of the population older than 60 years. A genetic predisposition to reflux disease has been proposed. In a twin study of reflux disease, concordance was greater in monozygotic than dizygotic twins. An association between BE and esophageal adenocarcinoma, the incidence of which has increased remarkably in the last few decades, has been established. Esophagogastric junction cancers can arise from small areas of cardia intestinal metaplasia (CIM). Regular endoscopic and histologic follow-up of BE patients is recommended. Surveillance of patients with CIM is not advised. Chromoendoscopy may help to detect areas of high-grade dysplasia (HGD). The ablation of BE, e.g. by PDT or argon plasma coagulation, is not yet proven to reduce the cancer risk. Esophagectomy is still the standard management of HGD. Endoscopic mucosal resection may be used for visible, localized lesions with HGD, and this technique may be combined with thermal ablation for areas of HGD without visible abnormality.

Effective intra-oesophageal acid suppression in patients with gastro-oesophageal reflux disease: lansoprazole vs. pantoprazole

BACKGROUND

: Effective intra-oesophageal acid suppression is an important therapeutic goal in complicated and atypical gastro-oesophageal reflux disease.

AIM

: To compare the efficacy of lansoprazole and pantoprazole in normalizing oesophageal acid exposure.

METHODS

: Fifty patients with complicated or atypical gastro-oesophageal reflux disease were randomly assigned to receive 30 mg lansoprazole (n = 26) or 40 mg pantoprazole (n = 24) once daily. Three to four weeks after the start of treatment, patients underwent 24-h oesophageal pH monitoring whilst on therapy. If the results were improved but still abnormal, the dosage was doubled and pH monitoring was repeated. If oesophageal acid exposure was not improved, the patient was shifted to the alternative drug regimen.

RESULTS

: Oesophageal acid exposure was normalized in all 26 patients treated with lansoprazole (in 35% of cases with a double daily dosage), whereas in six of the 24 (25%) patients treated with pantoprazole it was neither normalized nor lowered (P = 0.008). Accordingly, the mean percentage acid reflux time was significantly lower for the lansoprazole group (2.1) than for the pantoprazole group (5.8) (P = 0.032).

CONCLUSIONS

: Effective intra-oesophageal acid suppression can be accomplished more reliably with lansoprazole than with pantoprazole in patients with complicated and atypical gastro-oesophageal reflux disease.

Screening for esophageal adenocarcinoma: an evidence-based approach

Adenocarcinoma of the esophagus and the gastroesophageal junction is the twentieth most common malignancy in the United States. In developed countries, the incidence of esophageal adenocarcinoma is increasing 5% to 10% per year. Despite the use of endoscopy for earlier detection, mortality from esophageal adenocarcinoma has not declined. Using an evidence-based approach, we review screening methods for esophageal adenocarcinoma, including the use of a symptom questionnaire, identification of patients with a family history of Barrett's esophagus, peroral or transnasal endoscopy, barium swallow, fecal occult blood testing, and brush and balloon cytology. Screening has not been shown to reduce rate of progression of Barrett's esophagus to esophageal cancer. Many treatment options for dysplastic Barrett's esophagus or early carcinoma appear effective, but long-term follow-up data are not available. There is currently insufficient evidence supporting population-based screening for Barrett's esophagus. Several risk factors, including severe reflux symptoms, male sex, and obesity, may identify patients with gastroesophageal reflux disease who are at the greatest risk of the development of cancer.

Endoscopic treatment of early gastroesophageal malignancy

With the routine use of endoscopy, gastroesophageal cancers, which were often diagnosed in the symptomatic and incurable state, are now being diagnosed at earlier stages. Treatment of early-stage upper gastrointestinal cancers has evolved tremendously. Endoscopic therapy has been employed for early-stage lesions in an attempt to avoid the high morbidity and mortality associated with current curative procedures such as esophagectomy. These new endoscopic techniques include endoscopic mucosal resection, photodynamic therapy, electrocoagulation, and laser therapy. Exciting and novel endoscopic therapeutic options in diagnosing and treating early gastroesophageal cancers are the focus of this review.

Surveillance in Barrett's oesophagus: a personal view

Barrett's oesophagus is defined as columnar-lined oesophagus of any length containing specialised intestinal metaplasia. Diagnosis depends on close corroboration between the endoscopist and histopathologist. It occurs in 10% of patients presenting endoscopically with reflux symptoms and has an adenocarcinoma incidence of 0.4% to 2%. Surveillance is performed to detect precancerous change (dysplasia) and early stage disease has a good surgical prognosis. Computer models suggest cost efficacy comparable to other health measures. However most patients with Barrett's do not die of oesophageal cancer and elective oesophagectomy has an appreciable mortality. Endoscopic ablation techniques and improved definition of high risk subgroups will help shape future surveillance programmes.

In vivo characterization of colonic thermal injury caused by argon plasma coagulation

BACKGROUND

Argon plasma coagulation has been rapidly accepted for endoscopic obliteration of vascular lesions and superficial tumors. Depth of injury is thought to be limited through preferential discharge of energy to nondesiccated tissue. However, argon plasma coagulation-induced injury has not been well characterized. The aim of this study was to characterize argon plasma coagulation-induced colonic injury by using a porcine model.

METHODS

Laparotomy was performed in 6 female swine and the colon exteriorized with the subjects under general anesthesia. Lesions were made with an argon plasma coagulation probe held perpendicular and 2 mm from the mucosa. Variables studied were as follows: power (45 W, 60 W, and 75 W) and duration (1, 2, or 3 seconds; n = 11 for each power/duration combination). Injury was graded as either superficial or deep, involving the muscularis propria.

RESULTS

Circular muscle layer injury correlated closely with power (p = 0.02), duration (p = 0.001), and total energy delivered (r = 0.977). Longitudinal muscle damage was associated with duration of burn (p = 0.001) and total energy delivered (r = 0.855), but correlated poorly with power (p = 0.40). No perforations occurred. Submucosal injection of saline solution had a protective effect with reductions in circular (90% to 10%, p = 0.002) and longitudinal muscle injury (50% to 0%, p = 0.1).

CONCLUSIONS

Injury to the muscularis propria occurs at recommended settings for argon plasma coagulation. Injury correlates with power setting, duration of burn, and total energy delivery. Protective arcing to nondesiccated tissue does not appear to be significant in vivo. Submucosal injection of saline solution protects against deep injury.

Barrett's esophagus

Barrett's esophagus is an acquired condition resulting from severe esophageal mucosal injury. It still remains unclear why some patients with gastroesophageal reflux disease develop Barrett's esophagus whereas others do not. The diagnosis of Barrett's esophagus is established if the squamocolumnar junction is displaced proximal to the gastroesophageal junction and if intestinal metaplasia is detected by biopsy. Despite this seemingly simple definition, diagnostic inconsistencies remain a problem, especially in distinguishing short segment Barrett's esophagus from intestinal metaplasia of the gastric cardia. Barrett's esophagus would be of little importance were it not for its well-recognized association with adenocarcinoma of the esophagus. The incidence of esophageal adenocarcinoma continues to increase and the 5-year survival rate for this cancer remains dismal. However, cancer risk for a given patient with Barrett's esophagus is lower than previously estimated. Current strategies for improved survival in patients with esophageal adenocarcinoma focus on cancer detection at an early and potentially curable stage. This can be accomplished either by screening more patients for Barrett's esophagus or with endoscopic surveillance of patients with known Barrett's esophagus. Current screening and surveillance strategies are inherently expensive and inefficient. New techniques to improve the efficiency of cancer surveillance are evolving rapidly and hold the promise to change clinical practice in the future. Treatment options include aggressive acid suppression, antireflux surgery, chemoprevention, and ablation therapy, but there is still no clear consensus on the optimal treatment for these patients.

Hiatal hernia is the key factor determining the lansoprazole dosage required for effective intra-oesophageal acid suppression

BACKGROUND

Effective intra-oesophageal acid suppression can be achieved with lansoprazole. The daily dosage could be influenced by the presence of hiatal hernia.

AIM

To assess the lansoprazole daily dosage required to normalize oesophageal acid exposure in patients with and without hiatal hernia.

METHODS

Fifty patients with complications or atypical manifestations of gastro-oesophageal reflux disease were given lansoprazole, 30 mg once daily. Three to four weeks after the start of treatment, patients underwent oesophageal pH monitoring while on therapy. If the results were still abnormal, the lansoprazole dosage was doubled and 24-h pH-metry was repeated 20-30 days thereafter.

RESULTS

A 30-mg daily dosage of lansoprazole normalized oesophageal acid exposure in 70% of cases, whilst a 60-mg daily dosage was necessary in the remainder: the two groups differed only in the presence of hiatal hernia (28% vs. 100%, respectively; P=0.000). Effective intra-oesophageal acid suppression was obtained in all 25 patients without hiatal hernia with the 30-mg daily dosage of lansoprazole.

CONCLUSIONS

Hiatal hernia is the key factor determining the lansoprazole dosage required for effective intra-oesophageal acid suppression in complicated and atypical gastro-oesophageal reflux disease. High efficacy of a 30-mg daily dosage of lansoprazole can be predicted in the absence of hiatal hernia.

Role of mucosal ablative therapy in the treatment of the columnar-lined esophagus

With the high prevalence of gastroesophageal reflux-like symptoms in the United States and the association between GERD symptoms and the premalignant condition of BE, there is more and more demand for new and efficacious techniques to treat BE. A wide variety of endoscopic mucosal ablative techniques have been developed with promising initial results. Long-term control of neoplastic risk, however, has not been demonstrated, and most studies demonstrate that there is still potentially some intestinal mucosa present underneath squamous mucosa. Currently, more study is needed to determine which patient groups require therapy of any kind and to determine which therapies would be the most efficacious. Genetic markers may aid in identification of subgroups that are at risk for cancer and help to identify those who would respond to mucosal therapy. Even in patients who have HGD, subgroups of patients who have focal HGD have been found to have better prognosis than those who have more widespread HGD. Currently, there is sufficient information to consider mucosal ablative techniques in patients who are not good surgical candidates. Photodynamic therapy, APC, KTP, Nd:YAG and argon lasers, MPEC, and EMR may provide good alternatives, depending on the degree of dysplasia, the extent of disease, and the age of the patient. Photodynamic therapy and Nd:YAG laser therapy have been applied to more neoplastic lesions, whereas KTP:YAG, APC, and multipolar coagulation have been successful in nondysplastic Barrett's mucosa. In the future, there will be more information to justify the application of mucosal ablative therapy in selected patients.

An update on strategies for eradication of Barrett's mucosa

Barrett's esophagus is a complication of chronic gastroesophageal reflux disease and is characterized by replacement of the normal squamous mucosa in the distal esophagus with metaplastic columnar mucosa. It is the premalignant lesion for adenocarcinoma of the distal esophagus and the esophagogastric junction. Treatment of Barrett's esophagus includes controlling the underlying reflux with either proton pump inhibitor therapy or antireflux surgery. However, neither pharmacological nor surgical treatment has resulted in reversal of the metaplastic mucosa. Failure of conventional treatments has led to endoscopic ablation therapies-injury to the Barrett's esophagus with different forms of energy in combination with acid suppression. This article reviews the current status of different therapies for endoscopic reversal of Barrett's esophagus.

Current status of ablative therapies in esophageal disorders

Endoscopic ablative therapies for esophageal diseases have been used for palliation of inoperable esophageal cancer, but their use in eradication of early esophageal cancer and Barrett's esophagus (with and without dysplasia) has been reported in recent publications. Pharmacologic and surgical treatment of reflux symptoms in patients with Barrett's esophagus has not consistently reversed the metaplastic epithelium. This has led investigators to try different modalities of local injury to the columnar mucosa in an acid-reduced environment. Endoscopic reversal of Barrett's esophagus (visual replacement of columnar mucosa by squamous mucosa) is more readily achievable than complete histologic reversal. Preliminary data show that endoscopic reversal of Barrett's esophagus can be achieved, but intestinal metaplasia underlying the new squamous mucosa is reported in almost all series. Incidence of adenocarcinoma in patients with Barrett's without dysplasia is probably so low that endoscopic ablation as a therapy cannot be advocated outside of study protocols. Endoscopic therapy as a definitive treatment for patients with high-grade dysplasia (HGD) and/or early adenocarcinoma holds promise, especially in older patients with comorbid illnesses. Future long-term randomized studies are needed to determine whether ablative therapies can provide an alternative approach for patients with HGD and early cancer. Advanced cancers that are not resectable for cure can be effectively treated by endoscopic therapy for palliation of dysphagia.