Proceedings from an international conference on ablation therapy for Barrett's mucosa: Brittany, France, 31 August - 2 September 1997

Meta-analysis of biomarkers predicting risk of malignant progression in Barrett's oesophagus

BACKGROUND

Barrett's oesophagus is a precursor to the development of oesophageal adenocarcinoma. This study sought to clarify the role of genetic, chromosomal and proliferation biomarkers that have been the subjects of multiple studies through meta-analysis.

METHODS

MEDLINE, Embase, PubMed and the Cochrane Library were searched for clinical studies assessing the value of p53, p16, Ki-67 and DNA content abnormalities in Barrett's oesophagus. The main outcome measure was the risk of development of high-grade dysplasia (HGD) or oesophageal adenocarcinoma.

RESULTS

Some 102 studies, with 12 353 samples, were identified. Mutation (diagnostic odds ratio (DOR) 10·91, sensitivity 47 per cent, specificity 92 per cent, positive likelihood ratio (PLR) 4·71, negative likelihood ratio (NLR) 0·65, area under the curve (AUC) 0·792) and loss (DOR 16·16, sensitivity 31 per cent, specificity 98 per cent, PLR 6·66, NLR 0·41, AUC 0·923) of p53 were found to be superior to the other p53 abnormalities (loss of heterozygosity (LOH) and overexpression). Ki-67 had high sensitivity in identifying high-risk patients (DOR 5·54, sensitivity 82 per cent, specificity 48 per cent, PLR 1·59, NLR 0·42, AUC 0·761). Aneuploidy (DOR 12·08, sensitivity 53 per cent, specificity 87 per cent, PLR 4·26, NLR 0·42, AUC 0·846), tetraploidy (DOR 5·87, sensitivity 46 per cent, specificity 85 per cent, PLR 3·47, NLR 0·65, AUC 0·793) and loss of Y chromosome (DOR 9·23, sensitivity 68 per cent, specificity 80 per cent, PLR 2·67, NLR 0·49, AUC 0·807) also predicted malignant development, but p16 aberrations (hypermethylation, LOH, mutation and loss) failed to demonstrate any advantage over the other biomarkers studied.

CONCLUSION

Loss and mutation of p53, and raised level of Ki-67 predicted malignant progression in Barrett's oesophagus.

p53 immunohistochemical expression in Barrett's esophagus before and after endoscopic ablation by argon plasma coagulation

OBJECTIVE

Few studies have evaluated p53 accumulation in the squamous mucosa contiguous (SMC) to Barrett's esophagus (BE) and in the new squamous epithelium after endoscopic ablation. We evaluated the p53 expression in BE, in the SMC, and in the new squamous mucosa generated after ablation by argon plasma coagulation (APC).

MATERIAL AND METHODS

Endoscopic biopsy specimens from 37 BE patients, before and after ablation by APC, were analyzed. The p53 immunostaining criterion used was the staining of at least half of the nuclei.

RESULTS

p53 was detected in BE in 5 (13.5%) cases. In all these cases, SMC was p53(+). In addition, SMC was p53(-) in all cases of p53(-) BE (p <0.001). In the 5 cases with p53(+) BE and SMC, the new squamous mucosa continued to be p53(+). However, in the 32 cases with p53(-) SMC, the new squamous mucosa was also p53(-) (p <0.001). No case with p53(+) SMC turned out to be p53(-) after ablation. Similarly, no case with p53(-) BE and SMC before eradication became p53(+) after ablation (p < 0.001).

CONCLUSIONS

p53 was highly prevalent in the contiguous squamous mucosa when it is present in BE. After ablation, none of the cases lost p53 expression, and none of the negative cases turned out to be positive.

Audit of a Barrett's epithelium surveillance database

BACKGROUND

Barrett's epithelium is a premalignant condition in which endoscopic surveillance is recommended but remains contentious.

AIM

To audit our Barrett's epithelium surveillance database and to calculate the incidence and natural history of dysplasia and cancer in this cohort.

METHODS

A retrospective analysis of a computerised database of patients with columnar lined oesophagus containing specialised intestinal metaplasia was undertaken over a 5-year period. The surveillance protocol was annual endoscopy with 2-cm interval quadrantic biopsies with patients on continuous acid-suppression therapy.

RESULTS

A total of 138 (102 men) patients underwent active surveillance. The mean age was 62.1 years and the mean Barrett's epithelium length was 5.9 cm. Ten patients had low-grade dysplasia, with a mean age of 73.5 years, a mean Barrett's epithelium length of 7.8 cm, a prevalence of 7.2% over 5 years and an incidence of 1.4% per annum. Low-grade dysplasia regressed in five patients, persisted in four patients, and was associated with a concurrent squamous carcinoma in one patient. Three patients had high-grade dysplasia at index endoscopy, with no incident cases. One progressed to adenocarcinoma after 2 years. A cancer incidence of one per 202 patient-years of surveillance was found, equivalent to 0.5% per year.

CONCLUSION

Short-interval (1-year) endoscopic surveillance of Barrett's epithelium offers little reward. Low-grade dysplasia is uncommon, and no progression to adenocarcinoma was seen in this cohort. No incident high-grade dysplasia was observed. Prospective evaluation of a longer endoscopic surveillance interval in controlled clinical studies is warranted.

Barrett oesophagus and adenocarcinoma: an overview of epidemiologic, conceptual and clinical issues

A steady increase in the incidence of adenocarcinoma of the oesophagus and oesophagogastric junction has been observed in Western countries. Patients with distinctive-type Barrett oesophagus are predisposed to developing adenocarcinoma of the oesophagus. Distinctive-type Barrett oesophagus is defined by the presence of intestinal-like goblet cells anywhere in the oesophagus. Adenocarcinomas of the oesophagogastric junction may be associated with short segments of intestinal-type columnar epithelium in the distal oesophagus. Prognosis after surgical resection for cancer of the oesophagus or oesophagogastric junction is strongly affected by the extent of the disease at the time of diagnosis. The identification of Barrett oesophagus as a premalignant condition, the recognition of a stepwise neoplastic progression, along with the poor survival rates of advanced oesophageal adenocarcinoma have initiated the practice of endoscopic biopsy surveillance for patients with Barrett oesophagus. There is supporting evidence that endoscopic biopsy surveillance of Barrett oesophagus permits detection of malignancy at an early stage with favourable results after oesophageal resection. Endoscopic treatment modalities should at this time not be generally adopted in the management of patients with early invasive adenocarcinoma of the oesophagus or oesophagogastric junction.

Laparoscopic Ultrasonic Epithelial Ablation of the Lower Esophagus after Nissen Fundoplication in a Porcine Model: Assessment of Tissue Damage and Healing Process

A substantial population of patients with Barrett's esophagus has undergone antireflux surgery but still requires annual surveillance endoscopy. These patients would benefit from a definitive ablation of the Barrett's mucosa, which would remove the malignant potential of this disease. This study evaluates the efficacy of applying ultrasonic energy to remove the epithelium of the lower esophagus in a porcine model with prior Nissen fundoplication. Four Yakutan minipigs underwent laparoscopic Nissen fundoplication. After 2 weeks they underwent transgastric Cavitron ultrasonic surgical aspirator (CUSA; Valleylab, Boulder, CO) ablation of the lower esophageal epithelium. Healing of the mucosa was assessed by endoscopy at 2 weeks and pathological examination at 4 weeks after ablation. All pigs underwent successful laparoscopic Nissen fundoplication. Complete lower esophageal epithelial ablation was accomplished through the fundoplication in three animals. One pig developed a bezoar that prohibited ablation. At 2 weeks endoscopy showed patchy squamous epithelial regeneration, which was confirmed histologically. Esophageal specimens at 4 weeks showed complete regeneration of squamous epithelium with a partially healed small ulcer in one animal. No stricture formation was seen. We conclude that the CUSA technique can completely ablate Barrett's mucosa in the setting of a prior antireflux procedure. Healing with squamous mucosal regeneration is rapid and complete.

Rising incidence of esophageal adenocarcinoma in Western countries: is it possible to identify a population at risk?

Symptomatic gastroesophageal reflux disease (GERD) and Barrett's mucosa are risk factors for esophageal adenocarcinoma (ADC). The aim of this study was to analyze the anthropometric features and prevalence of GERD in patients with ADC compared with patients with squamous cell carcinoma (SCC) and control subjects. A total of 262 patients with ADC and 302 with SCC were enrolled consecutively. A control group of 262 individuals, sex and age matched to the ADC group, and an additional group of 138 patients with GERD confirmed by 24-h pH monitoring were used for comparison. The prevalence of symptomatic GERD was 32.4% in the subgroup of patients with Barrett's ADC (male-female=6.4:1; mean age=62 years) vs. 8% in those with gastric cardia carcinoma (P< 0.01), 3% in the SCC group (P< 0.01), and 10% in the control group (P< 0.01). ADC patients, controls and refluxers had similar body mass index (BMI) that was significantly higher than in the SCC group (P< 0.05). Whether surveillance endoscopy is indicated in men over 50 years with a long-lasting history of GERD and a BMI >25 remains to be determined.

Rising incidence of esophageal adenocarcinoma in Western countries: is it possible to identify a population at risk?

Symptomatic gastroesophageal reflux disease (GERD) and Barrett's mucosa are risk factors for esophageal adenocarcinoma (ADC). The aim of this study was to analyze the anthropometric features and prevalence of GERD in patients with ADC compared with patients with squamous cell carcinoma (SCC) and control subjects. A total of 262 patients with ADC and 302 with SCC were enrolled consecutively. A control group of 262 individuals, sex and age matched to the ADC group, and an additional group of 138 patients with GERD confirmed by 24-h pH monitoring were used for comparison. The prevalence of symptomatic GERD was 32.4% in the subgroup of patients with Barrett's ADC (male-female=6.4:1; mean age=62 years) vs. 8% in those with gastric cardia carcinoma (P< 0.01), 3% in the SCC group (P< 0.01), and 10% in the control group (P< 0.01). ADC patients, controls and refluxers had similar body mass index (BMI) that was significantly higher than in the SCC group (P< 0.05). Whether surveillance endoscopy is indicated in men over 50 years with a long-lasting history of GERD and a BMI >25 remains to be determined.

Antireflux surgery, highly selective vagotomy and duodenal switch procedure: post-operative evaluation in patients with complicated and non-complicated Barrett's esophagus

Antireflux surgery, highly selective vagotomy (HSV) and Roux-en-Y duodenojejunostomy have been suggested for control of pathophysiological factors involved in patients with Barrett's esophagus (BE). The aim of this study was to evaluate prospectively the results of this technique in patients with complicated (n = 21) and noncomplicated (n=45) BE. Complete evaluation of esophageal function, endoscopic histologic and clinical control was carried out before and 2 years after surgery. Post-operative results show recurrence of ulcer in patients with complicated BE, but no recurrence in patients with non-complicated BE. Preoperative esophageal ulcer and stricture were present in 85.3% and 14.3%, respectively, of patients with complicated BE. In this group, recurrence of these complications was 38.1% and 9.5% respectively. The technique offers excellent results in patients with non-complicated BE. However, in patients with complicated BE, the recurrence rate is higher, mainly because of the persistence of acid reflux into the esophagus.

Predictors of progression to cancer in Barrett's esophagus: baseline histology and flow cytometry identify low- and high-risk patient subsets

OBJECTIVE

Barrett's esophagus develops in 5-20% of patients with gastroesophageal reflux disease and predisposes to esophageal adenocarcinoma. The value of endoscopic biopsy surveillance is questioned because most patients do not develop cancer. Furthermore, observer variation in histological diagnosis makes validation of surveillance guidelines difficult because varying histological interpretations may lead to different estimated rates of progression. Thus, objective biomarkers need to be validated for use with histology to stratify patients according to their risk for progression to cancer.

METHODS

We prospectively evaluated patients using a systematic endoscopic biopsy protocol with baseline histological and flow cytometric abnormalities as predictors and cancer as the outcome.

RESULTS

Among patients with negative, indefinite, or low-grade dysplasia, those with neither aneuploidy nor increased 4N fractions had a 0% 5-yr cumulative cancer incidence compared with 28% for those with either aneuploidy or increased 4N. Patients with baseline increased 4N, aneuploidy, and high-grade dysplasia had 5-yr cancer incidences of 56%, 43%, and 59%, respectively. Aneuploidy, increased 4N, or HGD were detected at baseline in all 35 patients who developed cancer within 5 yr.

CONCLUSIONS

A systematic baseline endoscopic biopsy protocol using histology and flow cytometry identifies subsets of patients with Barrett's esophagus at low and high risk for progression to cancer. Patients whose baseline biopsies are negative, indefinite, or low-grade displasia without increased 4N or aneuploidy may have surveillance deferred for up to 5 yr. Patients with cytometric abnormalities merit more frequent surveillance, and management of high-grade dysplasia can be individualized.

Malignant degeneration of Barrett's esophagus: clinical point of view

The incidence of adenocarcinoma of the distal esophagus is increasing at an alarming rate. Intestinal metaplasia in the distal esophagus, i.e. Barrett's esophagus, has been identified as the single most important risk factor for these tumors. Barrett's esophagus develops as a consequence of chronic mucosal injury in up to 10% of patients with long-lasting gastroesophageal reflux disease. Experimental and clinical data indicate that adenocarcinoma of the distal esophagus is a direct consequence of mixed (i.e., acid and bile) reflux into the esophagus. Interestingly, Helicobacter pylori infection of the stomach appears to exert a protective effect against the development of esophageal adenocarcinoma. Neither aggressive medical acid suppression nor antireflux surgery can induce a predictable regression of Barrett's esophagus or exert a protective effect against its malignant degeneration. Endoscopic ablation of Barrett's esophagus, although appealing, currently constitutes a potentially dangerous procedure without proven benefit for the patient. Since the development of Barrett's adenocarcinoma follows a multistep process from metaplasia through increasingly severe grades of dysplasia, close endoscopic surveillance with extensive biopsies currently remains the only means to identify patients at risk for malignant degeneration and detect esophageal adenocarcinoma at an early and curable stage.

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

Besides esophagectomy and antireflux therapy with intensive endoscopic surveillance, endoscopic ablation therapy is a new treatment modality for Barrett's esophagus (BE) with high-grade dysplasia (HGD). Endoscopic surgical ablation can be performed by either a thermal, chemical, or mechanical method. This article describes the current management of patients with BE and HGD and the various methods of endoscopic ablation, including multipolar electrocoagulation, argon plasma beam coagulation, contact laser photoablation, and photodynamic therapy. It also summarizes the results of 37 patient studies, case reports, and abstracts on experimental endoscopic therapies for BE. The advantages and disadvantages of the various treatment possibilities are considered, and the future direction of the management of BE is discussed.

Biology of gastroesophageal reflux disease: pathophysiology relating to medical and surgical treatment

This chapter reviews the biology of gastroesophageal reflux disease, relating pathophysiology to medical and surgical therapy. Various definitions of the disease are presented and workable criteria are developed to identify patients with the disease. The central importance of the lower esophageal high-pressure zone as a barrier to reflux is emphasized, along with an analysis of its biomechanical alteration in disease. The composition of the refluxed gastric juice is characterized in regard to its potential for mucosal injury. Evidence is provided that cardiac-type mucosa is an acquired sequel to acid-induced squamous mucosal injury in the terminal esophagus. A hypothesis regarding the process of intestinalization of cardiac-type mucosa to form Barrett's esophagus is presented. An integrated concept of the pathophysiology of gastroesophageal reflux disease is constructed. Practical concepts regarding the treatment of gastroesophageal reflux disease are developed, based on a review of studies on the natural history of the disease and the long-term outcome of therapy.

Reflux esophagitis and gastroesophageal reflux disease: a cross-sectional study of gastroesophageal reflux disease patients by age group

The purpose of this study was to explore the relationship between the intensity of acid reflux and severity of esophageal tissue damage in a cross-sectional study of patients with gastroesophageal reflux disease (GERD). Seventy-eight patients with were selected in accordance with the strict 24-hour ambulatory esophageal pHmetry (24h-pHM) criteria and distributed into three age groups: Group A: 14-24 years of age. Group B: 25-54; and Group C: 55-64. The 24h-pHM was carried out in accordance with DeMeester standardization, and the Savary-Miller classification for the diagnosis of reflux esophagitis was used. The groups were similar in 24h-pHM parameters (p > 0.05), having above normal values. For the study group as a whole, there was no correlation between age group and intensity of acid reflux, and there was no correlation between intensity of acid reflux and severity of esophageal tissue damage. However, when the same patients were sub-grouped in accordance with the depth of their epithelial injury and then distributed into age groups, there was a significant difference in esophagitis without epithelial discontinuity. Younger patients had less epithelial damage than older patients. Additionally, although there was a significant progression from the least severe to the moderate stages of epithelial damage among the age groups, there was no apparent difference among the age groups in the distribution between the moderate stages and most severe stages. The findings support the conclusion that the protective response of individuals to acid reflux varies widely. Continued aggression by acid reflux appears to lead to the exhaustion of individual mechanisms of epithelial protection in some patients, but not others, regardless of age or duration of the disease. Therefore, the diagnosis and follow-up of GERD should include both measurements of the quantity of refluxed acid and an assessment of the damage to the esophageal epithelium.