Section I: epidemiological review.

The incidence of esophageal adenocarcinoma has increased tremendously in the United States and other Western countries over the past 30 years while the incidence of esophageal squamous cell carcinoma has remained unchanged. The rate of increase in incidence is higher than for any other cancer. The reasons for this are multifactorial. Despite this, esophageal cancer remains a relatively uncommon malignancy. Barrett's esophagus (BE) is the most important risk factor for the development of esophageal adenocarcinoma and is believed to be the precursor lesion for most. The risk of developing esophageal adenocarcinoma from known BE is estimated to be 0.5% per patient year. Persistent high-grade dysplasia in BE is a sensitive indicator for the development of esophageal adenocarcinoma. However, only a minority of patients with BE are ever diagnosed and, therefore, surveillance endoscopy in Barrett's patients has failed to affect the incidence of esophageal adenocarcinoma. The relationship of Helicobacter pylori to esophageal adenocarcinoma is complex, but nonsteroidal antiinflammatory drugs may confer protection against the development of this cancer. Fortunately, improved survival is being seen with both squamous cell esophageal carcinoma and esophageal adenocarcinoma. Additional study is required to better determine the risk factors for the development of esophageal cancer, and epidemiologic understanding will prove important in developing methods of detection and therapeutic intervention for this disease.