[Geography of cancer of the esophagus]

A review of available data on the epidemiology of oesophageal cancer from different parts of the world as well as an analysis of new findings, suggests the following conclusions: 1. A peculiar incidence pattern of the disease exists worldwide with roughly 500-fold differences in rates (truncated) between the highest and lowest risk areas. 2. Males are generally affected more than females, with a few exceptions such as the very high risk regions of northern Iran. The highest male: female sex ratios (based on truncated incidence rates) have been reported from Normandy and Brittany (25:1) and the lowest ratios from South Gorgan in northern Iran (0.5:1). 3. There is evidence that the frequency of oesophageal cancer is rising over time in many regions, particularly among the black population of the United States and in England and France. 4. Most of the areas reflecting a very high incidence of this disease are located in poorer parts of the world. 5. The frequency of this disease varies among the native and migrated population in different countries.