Preventing death of Barrett's cancer: does frequent surveillance endoscopy do it?

BOB CAT: A Large-Scale Review and Delphi Consensus for Management of Barrett's Esophagus With No Dysplasia, Indefinite for, or Low-Grade Dysplasia

OBJECTIVES

Barrett's esophagus (BE) is a common premalignant lesion for which surveillance is recommended. This strategy is limited by considerable variations in clinical practice. We conducted an international, multidisciplinary, systematic search and evidence-based review of BE and provided consensus recommendations for clinical use in patients with nondysplastic, indefinite, and low-grade dysplasia (LGD).

METHODS

We defined the scope, proposed statements, and searched electronic databases, yielding 20,558 publications that were screened, selected online, and formed the evidence base. We used a Delphi consensus process, with an 80% agreement threshold, using GRADE (Grading of Recommendations Assessment, Development and Evaluation) to categorize the quality of evidence and strength of recommendations.

RESULTS

In total, 80% of respondents agreed with 55 of 127 statements in the final voting rounds. Population endoscopic screening is not recommended and screening should target only very high-risk cases of males aged over 60 years with chronic uncontrolled reflux. A new international definition of BE was agreed upon. For any degree of dysplasia, at least two specialist gastrointestinal (GI) pathologists are required. Risk factors for cancer include male gender, length of BE, and central obesity. Endoscopic resection should be used for visible, nodular areas. Surveillance is not recommended for <5 years of life expectancy. Management strategies for indefinite dysplasia (IND) and LGD were identified, including a de-escalation strategy for lower-risk patients and escalation to intervention with follow-up for higher-risk patients.

CONCLUSIONS

In this uniquely large consensus process in gastroenterology, we made key clinical recommendations for the escalation/de-escalation of BE in clinical practice. We made strong recommendations for the prioritization of future research.

Molecular biology of esophageal cancer in the genomics era

The incidence of esophageal adenocarcinoma is rising in the United States and Western countries. Significant differences exist between esophageal adenocarcinoma and squamous cell carcinoma in the molecular mechanisms responsible for the tumorigenesis process. State-of-the-art techniques such as gene microarrays and proteomics will greatly aid in the development of new therapies targeting specific molecular pathways,ultimately leading to improved survival in patients who have esophageal cancer.

Multiple management modalities in esophageal cancer: epidemiology, presentation and progression, work-up, and surgical approaches

Annually, approximately 13,200 people in the U.S. are diagnosed with esophageal cancer and 12,500 die of this malignancy. Of new cases, 9,900 occur in men and 3,300 occur in women. In part I of this two-part series, we explore the epidemiology, presentation and progression, work-up, and surgical approaches for esophageal cancer. In the 1960s, squamous cell cancers made up greater than 90% of all esophageal tumors. The incidence of esophageal adenocarcinomas has risen considerably over the past two decades, such that they are now more prevalent than squamous cell cancer in the western hemisphere. Despite advances in therapeutic modalities for this disease, half the patients are incurable at presentation, and overall survival after diagnosis is grim. Evolving knowledge regarding the etiology of esophageal carcinoma may lead to better preventive methods and treatment options for early stage superficial cancers of the esophagus. The use of endoscopic ultrasound and the developing role of positron emission tomography have led to better diagnostic accuracy in this disease. For years, the standard of care for esophageal cancer has been surgery; there are several variants of the surgical approach. We will discuss combined modality approaches in part II of this series.

Dysplasia in Barrett esophagus

BACKGROUND

Dysplasia in Barrett esophagus is a premalignant condition that is associated with an increased risk of developing esophageal adenocarcinoma. Unfortunately, clinical investigation aimed at prevention of progression to malignant disease has been hampered by the variable prevalence of dysplasia reported in the literature. The objective of the current study was to more accurately determine the prevalence of dysplasia among individuals with Barrett esophagus who would be available for enrollment in a chemoprevention trial.

METHODS

The pathology archives of 3 institutions were reviewed over a 5-year period for all reports of diagnoses of Barrett esophagus. Surgical cases, malignancies, and duplicate or referral cases were excluded from the analysis.

RESULTS

A total of 790 cases of Barrett esophagus were identified. Of these, 37 (4.7%) were cases of low-grade dysplasia (LGD), and 20 (2.5%) were cases of high-grade dysplasia. The University of Michigan Medical Center (Ann Arbor, MI) diagnosed 18 cases of LGD, Henry Ford Hospital (Detroit, MI) diagnosed 15 cases of LGD, and Brigham and Women's Hospital (Boston, MA) diagnosed 4 cases of LGD in patients with Barrett esophagus over the 5-year study period.

CONCLUSIONS

The confirmed low prevalence of cases of LGD will affect the design of future clinical trials of chemopreventive interventions for Barrett esophagus.

Endoscopic diagnosis and surveillance of Barrett's esophagus

There are many questions regarding the screening and surveiliance of BE for which there are currently no answers. Despite the use of models and extrapolations by some authors to suggest that screening and surveiliance for a cancer of such low incidence will never be justified, others argue just as vociferously that given the continued epidemic rise in incidence of this cancer, the uniformly fatal outcome of these cancers if dianosed after symptoms occur, and the enormous pool of patients remaining at risk for future cancer development, a focused and prudent screening and surveillance strategy for Barrett's-related esophageal adenocarcinoma is justified. The data also show that a single screening examination is probably as effective as almost all subsequent surveilance examinations in detecting advanced neoplasia, and much of the current resource use and energy for screening and surveillance in BE should be directed toward screening. Whether screening should be offered or recommended to only older patients (> 50-55 years), whites, and men is unknown, but it is premature to adopt this strategy until better evidence exist supporting a restricted screening policy. Regarding the optimal surveilance frequency and technique, examinations more frequent than every 3 to 5 years are not justifiable, and until proven otherwise, biopsy specimens should be obtained with the largest forceps that can be used with the endoscopic instrument and "saturation" biopsies from the Barrett's obtained. It is unlikely that too many biopsy specimens can be taken. Furthermore, the safety of this approach has been, proven. It is quite likely that the inverse is not true; clinicians likely can do much more harm by taking too few biopsy specimens. It is hoped that the current intense interest in Barrett's neoplasia allows clinicians to address these critical issues in the years to come and resolve this clinical conundrum.