Concepts in the prevention of adenocarcinoma of the distal esophagus and proximal stomach.

For decades, the incidence rates for squamous cell carcinoma of the esophagus and adenocarcinoma of the distal stomach have been declining while the rates for adenocarcinomas of the esophagus and gastric cardia have increased profoundly. Recent studies have shown that the gastroesophageal junction (GEJ) is regularly exposed to concentrated gastric acid and to a variety of nitrosating species, noxious agents that may contribute to carcinogenesis in this region. For adenocarcinomas that straddle the GEJ, it can be difficult to determine whether the tumor originated in the esophagus or in the gastric cardia. This classification problem hampers studies on the epidemiology and pathogenesis of GEJ tumors. Current concepts in the prevention of cancers of the distal esophagus and proximal stomach have emerged from advances in our understanding of the specific molecular events that occur during the evolution of these tumors. This report reviews those events and focuses on current concepts in the prevention of adenocarcinomas at the GEJ. The similarities and differences in risk factors, molecular pathogenesis, and in preventive strategies for adenocarcinomas of the esophagus and gastric cardia are highlighted.