In BE, the normal squamous epithelium of the esophagus is replaced by a metaplastic columnar epithelium not normally found in the human body - known as specialized columnar epithelium. (Figure 1: Dysplasia in Barrett's Esophagus). This tissue develops into cancer via a multistep process that fortunately permits time for early diagnosis and intervention. The progression is for patients to progress from esophagitis, to BE, to high-grade dysplasia, to adenocarcinoma.
Therefore, patients with chronic GERD should undergo an endoscopy to look for the presence of BE. When BE is identified, these patients should undergo periodic endoscopy with biopsy. In the past, routine morphology had been used as a diagnostic criteria. However, since cancer is characterized by abnormal genetic processes, this permits the use of novel cellular assays using DNA content flow cytometry. Biopsy material is processed and a DNA histogram developed to determine the prevalence of genomic instability in biopsied cells (increased aneuploidy or G2/tetraploidy populations).
In the presence of BE, biopsy mapping should be done at multiple esophageal sites. There is an increase in histologic abnormalities as the severity of the disease progresses, making these assay results somewhat predictive of the progression of the disease. Pathology, however, does not provide the gold standard because of differences observed in pathologists' ability to identify high-grade dysplasia (HGD). Further it is known that 73% of patients with HGD remain stable or regress over a 2-3 years period, and so immediate operation, i.e. esophagectomy, is not always required. Therefore appropriate and careful surveillance is needed and when this has been done, survival has approached 100% over 5 years at the University of Washington.
There are no convincing data to support the use of any specific therapy for BE. Therefore, the most important approach is the need to continue esophageal biopsy surveillance in order to identify the presence and progression of metaplastic cells to dysplasia and early carcinoma-in-situ.
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