Endoscopic ablation therapy for Barrett's esophagus with high-grade dysplasia: a review

Secondary chemoprevention of Barrett's esophagus with celecoxib: results of a randomized trial

BACKGROUND

Barrett's esophagus is a premalignant condition that is a risk factor for the development of esophageal adenocarcinoma, a disease whose incidence is rapidly increasing. Because aspirin and other nonsteroidal anti-inflammatory drugs, such as celecoxib, may decrease the risk of developing esophageal cancer, we investigated the effect of long-term administration of celecoxib in patients with Barrett's esophagus with dysplasia.

METHODS

Chemoprevention for Barrett's Esophagus Trial (CBET) is a phase IIb multicenter randomized placebo-controlled trial of celecoxib in patients with Barrett's esophagus and low- or high-grade dysplasia. Patients were randomly assigned to treatment with 200 mg of celecoxib or placebo, both administered orally twice daily, and then stratified by grade of dysplasia. The primary outcome was the change from baseline to 48 weeks of treatment in the proportion of biopsy samples with dysplasia between the celecoxib and placebo arms. Secondary and tertiary outcomes included evaluation of changes in histology and expression levels of relevant biomarkers. All statistical tests were two-sided.

RESULTS

From April 1, 2000, through June 30, 2003, 222 patients were registered into CBET, and 100 of them with low- or high-grade Barrett's dysplasia were randomly assigned to treatment (49 to celecoxib and 51 to placebo). After 48 weeks of treatment, no difference was observed in the median change in the proportion of biopsy samples with dysplasia or cancer between treatment groups in either the low-grade (median change with celecoxib = -0.09, interquartile range [IQR] = -0.32 to 0.14 and with placebo = -0.07, IQR = -0.26 to 0.12; P = .64) or high-grade (median change with celecoxib = 0.12, IQR = -0.31 to 0.55, and with placebo = 0.02, IQR = -0.24 to 0.28; P = .88) stratum. No statistically significant differences in total surface area of the Barrett's esophagus; in prostaglandin levels; in cyclooxygenase-1/2 mRNA levels; or in methylation of tumor suppressor genes p16, adenomatous polyposis coli, and E-cadherin were found with celecoxib compared with placebo.

CONCLUSIONS

Administration of 200 mg of celecoxib twice daily for 48 weeks of treatment does not appear to prevent progression of Barrett's dysplasia to cancer.

Secondary chemoprevention of Barrett's esophagus with celecoxib: results of a randomized trial

BACKGROUND

Barrett's esophagus is a premalignant condition that is a risk factor for the development of esophageal adenocarcinoma, a disease whose incidence is rapidly increasing. Because aspirin and other nonsteroidal anti-inflammatory drugs, such as celecoxib, may decrease the risk of developing esophageal cancer, we investigated the effect of long-term administration of celecoxib in patients with Barrett's esophagus with dysplasia.

METHODS

Chemoprevention for Barrett's Esophagus Trial (CBET) is a phase IIb multicenter randomized placebo-controlled trial of celecoxib in patients with Barrett's esophagus and low- or high-grade dysplasia. Patients were randomly assigned to treatment with 200 mg of celecoxib or placebo, both administered orally twice daily, and then stratified by grade of dysplasia. The primary outcome was the change from baseline to 48 weeks of treatment in the proportion of biopsy samples with dysplasia between the celecoxib and placebo arms. Secondary and tertiary outcomes included evaluation of changes in histology and expression levels of relevant biomarkers. All statistical tests were two-sided.

RESULTS

From April 1, 2000, through June 30, 2003, 222 patients were registered into CBET, and 100 of them with low- or high-grade Barrett's dysplasia were randomly assigned to treatment (49 to celecoxib and 51 to placebo). After 48 weeks of treatment, no difference was observed in the median change in the proportion of biopsy samples with dysplasia or cancer between treatment groups in either the low-grade (median change with celecoxib = -0.09, interquartile range [IQR] = -0.32 to 0.14 and with placebo = -0.07, IQR = -0.26 to 0.12; P = .64) or high-grade (median change with celecoxib = 0.12, IQR = -0.31 to 0.55, and with placebo = 0.02, IQR = -0.24 to 0.28; P = .88) stratum. No statistically significant differences in total surface area of the Barrett's esophagus; in prostaglandin levels; in cyclooxygenase-1/2 mRNA levels; or in methylation of tumor suppressor genes p16, adenomatous polyposis coli, and E-cadherin were found with celecoxib compared with placebo.

CONCLUSIONS

Administration of 200 mg of celecoxib twice daily for 48 weeks of treatment does not appear to prevent progression of Barrett's dysplasia to cancer.

Computerized morphometry as an aid in determining the grade of dysplasia and progression to adenocarcinoma in Barrett's esophagus

The aims of this study were to use computerized morphometry in order to differentiate between the degree of dysplasia and to predict progression to invasive adenocarcinoma in Barrett's esophagus (BE). Biopsies from 97 patients with BE graded by a consensus forum of expert gastrointestinal pathologists were available for morphometrical analysis. The study group included 36 biopsies negative for dysplasia (ND), none of which progressed to carcinoma; 16 indefinite for dysplasia (IND) and 21 low-grade dysplasia (LGD), of which three progressed in each group and 24 high-grade dysplasia (HGD), of which 15 progressed to invasive carcinoma. Computerized morphometry was used for measuring indices of size, shape, texture, symmetry and architectural distribution of the epithelial nuclei. Low-grade dysplasia was best differentiated from the ND group by nuclear pseudostratification (P=0.036), pleomorphism (P<0.01), and chromatin texture (margination, P<0.01) and from the HGD group by nuclear area (P<0.01), pleomorphism (P<0.01), chromatin texture (margination, P<0.01), symmetry (P<0.01), and orientation (P=0.027). These results were validated on a new set of cases (n=55) using a neural network model, resulting in an accuracy of 89% for differentiating between the ND and LGD groups and 86% for differentiating between the LGD and HGD groups. Within the HGD group, univariate significant predictors of the progression interval to carcinoma were: indices of nuclear texture (heterogeneity: P=0.0019, s.d.-OD: P=0.005) and orientation: P=0.022. Nuclear texture (heterogeneity) was the only independent predictor of progression (P=0.004, hazard=11.54) by Cox's multivariate test. This study proposes that computerized morphometry is a valid tool for determining the grade of dysplasia in BE. Moreover, histomorphometric quantification of nuclear texture is a powerful tool for predicting progression to invasive adenocarcinoma in patients with HGD.

Management of gastroesophageal reflux disease

Gastroesophageal reflux disease is the most common and expensive digestive disease with complex and multi-factorial pathophysiologic mechanisms. Transient inappropriate relaxation of the lower esophageal sphincter is the predominant mechanism in the majority of patients with mild to moderate disease. Hiatal hernias and a reduced lower esophageal sphincter pressure have a significant role in patients with moderate to severe disease. Typical manifestations of gastroesophageal reflux disease include heartburn, regurgitation, and dysphagia. Atypical symptoms, such as noncardiac chest pain, pulmonary manifestations of asthma, cough, aspiration pneumonia, or ENT manifestations of globus and laryngitis, can be seen in patients with or without typical symptoms of gastroesophageal reflux disease. Endoscopy and ambulatory pH tests are best to evaluate the anatomic and physiologic impact ofgastroesophageal reflux disease. Complications of chronic gastroesophageal reflux disease include peptic strictures and Barrett metaplasia. Barrett esophagus is a major risk factor for esophageal adenocarcinoma, and upper endoscopy with surveillance biopsies is recommended for patients with Barrett esophagus. Medical therapy with anti-secretory agents (H2 blockers and proton pump inhibitors) is effective for most patients with gastroesophageal reflux disease. Surgical fundoplications and endoscopic treatment modalities are mechanical treatment options for patients with gastroesophageal reflux disease.

Barrett esophagus: update for radiologists

Barrett esophagus is a well-recognized entity in which there is progressive columnar metaplasia of the lower esophagus due to longstanding gastroesophageal reflux and reflux esophagitis [1]. This condition is important because it is associated with an increased risk of developing esophageal adenocarcinoma by a well-established sequence from dysplasia to carcinoma [2]. During the past decade, however, an explosion of new data has dramatically affected our understanding of Barrett esophagus. Not only have revised histopathologic criteria been developed for this condition, but it is currently believed that patients with Barrett esophagus should be classified as having "short-segment" or "long-segment" disease based on the extent of columnar metaplasia in the distal esophagus. This distinction has important implications for the risk of developing esophageal adenocarcinoma and subsequent need for endoscopic surveillance. The purpose of this article is to present these new concepts about Barrett esophagus and provide radiologists with a more current framework for diagnosing this condition.

Barrett's esophagus: histopathologic definitions and diagnostic criteria

Adenocarcinoma of the distal esophagus is rising more rapidly in incidence than any other visceral malignancy in the Western world. It is well established that most, if not all, of these tumors develop in Barrett's esophagus via the metaplasia-dysplasia-carcinoma sequence and could theoretically be detected at an early stage, but despite this, the majority of these tumors are still detected late in their course. This highlights the fact that the goal of effective surveillance for patients at risk for developing an adenocarcinoma of the distal esophagus is still far off. In addition, adenocarcinomas of the esophagogastric junction and gastric cardia are also rising in incidence, but their carcinogenesis and their relation to Barrett's esophagus are still being defined, as are the meaning and significance of the relatively new entities "short-segment Barrett's" and "ultra-short-segment Barrett's". This review attempts to clarify the main histopathologic issues concerned with the definition of Barrett's esophagus, its distinction from intestinal metaplasia of the gastric cardia, as well as the criteria for the histologic diagnosis of dysplasia and carcinoma in Barrett's esophagus.

Photodynamic therapy for Barrett's esophagus with dysplasia and/or early stage carcinoma: long-term results

BACKGROUND

Photodynamic therapy has been shown to eliminate Barrett's dysplasia. This report presents long-term follow-up data after photodynamic therapy of Barrett's esophagus with high-grade dysplasia, low-grade dysplasia, or early stage carcinoma.

METHODS

Porfimer-photodynamic therapy was performed in 103 patients. The Nd:YAG laser was used to photoablate small areas of residual or untreated Barrett's mucosa. Acid suppression was maintained in all patients (omeprazole, 20 mg twice a day).

RESULTS

Mean follow-up was 50.65 (SD 20.57) months (range 2-122 months). For the 82 patients not lost to follow-up, mean follow-up was 58.5 (12.89) months (range 41-132 months). After photodynamic therapy, the length of Barrett's mucosa decreased by a mean of 6.92 cm (range 1-22 cm). Of the 65 patients with high-grade dysplasia, 60 (94%) had elimination of high-grade dysplasia. Three (4.6%) patients developed subsquamous adenocarcinoma. Subsquamous, nondysplastic, metaplastic epithelium was found in 4 patients (4.9%). Strictures occurred in 18% with one session of photodynamic therapy, and 50% with two treatments, 30% overall. For the 103 patients, intention-to-treat success rates were 92.9%, 77.5%, and 44.4% for, respectively, low-grade dysplasia, high-grade dysplasia, and early stage carcinoma groups.

CONCLUSION

Porfimer-photodynamic therapy with supplemental Nd:YAG photoablation and continuous treatment with omeprazole reduces the length of Barrett's mucosa, eliminates high-grade dysplasia, and, by comparison with historical data, may reduce the expected frequency of carcinoma.

Barrett's Esophagus: Ablative Endoscopic Techniques

Barrett's esophagus consists of a precancerous condition in which the progression from dysplasia to adenocarcinoma is now well documented. The management of patients affected by Barrett's esophagus is still debatable, in particular for the risk of surgical treatment in the presence of small precancerous lesions or early adenocarcinoma. Furthermore, quality of life after surgical resection is often poor. Endoscopy is the main diagnostic and follow-up procedure in Barrett's esophagus: it allows the detection and treatment of severe dysplasia and invasive esophageal adenocarcinoma. Endoscopic treatment also produces reduction or disappearance of intestinal metaplasia. In these cases, the aim of the treatment is to prevent dysplastic changes. Moreover, the ideal endoscopic treatment should be safe, easy to perform and cost effective. Thermal (electrocoagulation, laser, argon-plasma coagulation), photochemical (photodynamic therapy) or ablative (endoscopic mucosal resection) procedures have been proposed alone or in combination, with the aim to completely eradicate dysplastic lesions or early adenocarcinoma as an alternative to surgical treatment. Endoscopic removal of the lesions is followed by restoration of normal epithelium. Some questions about patient selection, prevention of recurrence and best endoscopic treatment still remain unanswered.