Epidemiology of esophageal cancer: Orient to Occident. Effects of chronology, geography and ethnicity

Esophageal adenocarcinoma (EAC) has been rapidly increasing in Western countries during the past half century, especially in white men. Esophageal squamous cell carcinoma (ESCC) used to be the dominant type of esophageal malignancy both in Western and Asian countries. The rapid increase of EAC in Western countries has occurred in parallel with an increased prevalence of gastroesophageal reflux disease (GERD) and its major determinant, obesity. Such an increase in EAC has not yet been observed in Asia, despite a recent increase in prevalence of GERD. In this mini-review, we analyze possible factors influencing such east-west ('Orient to Occident') differences, particularly possible roles of ethnicity and environmental factors, such as Helicobacter pylori infection and nutritional factors, and how these might interact with socioeconomic differences. Development of Barrett's esophagus and esophageal adenocarcinoma appears to be strongly affected by ethnic factors, with populations resident at the west end of the Eurasian continent, such as Anglo-Celtics, being more prone to both conditions. On the other hand, ethnic groups from the eastern and southern ends of Eurasia, such as Chinese, Koreans and Japanese, and Africans might be more prone to developing esophageal squamous cell carcinoma. Future trends will also be discussed.