Barrett esophagus and cancer: pathogenesis, carcinogenesis, and diagnostic dilemmas

A metaplastic process, in which native squamous epithelium of the distal esophagus is replaced by columnar epithelium, is known as Barrett esophagus (BE). Over the past years, intestinal metaplasia was recognized as a marker for BE. The risk for the development of esophageal adenocarcinoma in a patients with BE is much higher when compared to the normal population. Duodeno-gastro-esophageal reflux is supposed to play a role in the pathogenesis of BE and rising incidence of adenocarcinoma of the esophagus. With current therapeutic options, when clinical manifestation of this cancer occurs, it is too late for cure in the majority of patients. Therefore, attention should be focused on early diagnosis, for which molecular genetic techniques might become available. Current data on genetic alterations involved in carcinogenesis of BE are discussed. Grading of dysplasia in BE carries important clinical consequences for the individual patient: intensification of endoscopic surveillance or 'prophylactic esophagectomy'. Several morpho- and/or cytometric parameters may be used for discrimination between different grades of dysplasia in BE. Therefore, a new and original algorythm for the potential application of quantitative pathology in grading of dysplasia in patients with BE has been proposed. Molecular biology together with image analysis of histological spectrum of BE enable better understanding of the mechanisms of malignant degeneration and might ultimately lead to targeted cancer prevention and/or therapeutic interventions.