There are two types of esophageal cancer: squamous cell carcinoma and adenocarcinoma. In the past, squamous cell carcinoma of the upper or mid esophagus was the most common type of esophageal cancer as a result of excessive smoking and alcohol consumption. Over the past few decades, a shift has occurred and now adenocarcinoma of the lower esophagus, or junction between the esophagus and stomach, has become the most common. This is a direct result of the increased prevalence of gastroesophageal reflux disease. As chronic reflux injures the lining of the esophagus, the cells change into a premalignant condition known as Barrett’s esophagus. Further injury and genetic changes can allow Barrett’s esophagus to progress into dysplasia, and finally into invasive adenocarcinoma.