Epidemiology of Esophageal Cancer: A Review

The purpose of studying the epidemiology of a particular cancer is principally twofold. First, to identify factors whose modification may reduce that cancer’s incidence and, secondly, a more general aim, to understand better the mechanisms that modify risk for cancer in human populations. For cancer of the esophagus, considerable success has been achieved in attaining both aims. In some areas of the world specific factors have been identified, control of which would eliminate most of the disease. In other areas, particularly where the disease is common, the epidemiological evidence points overwhelmingly to the role of environmental factors in determining risk. It seems, however, that the role of environmental factors is not as simple as, for example, the role of cigarette smoking in lung cancer where a single factor is the major determinant of risk. High risk for esophageal cancer usually results from the interaction of several factors, in particular environmental factors which modify host or tissue susceptibility. Elucidating the mechanism by which these interactions operate should not only provide insight into how practical intervention might be achieved, but also may serve as a more general model for carcinogenesis in humans. The purpose of this chapter is to give the evidence supporting these conclusions, presenting the worldwide occurrence of the disease and reviewing the many analytic epidemiological studies that have been performed.