The causes for esophageal cancer in the U.S. differ depending in what type of cancer is being considered. The risk factors for squamous cell cancer include smoking tobacco and heavy use of alcohol. People who are infected with human papilloma virus are also at increased risk. Those who suffer from achalasia (a benign esophageal disease), chronic scarring of the esophagus due to prior injury, or tylosis (a rare genetic disorder) are also at increased risk.

The risk factors for adenocarcinoma are less well understood. People who have Barrett's esophagus, an abnormal lining of the bottom part of the esophagus that is related to acid reflux problems, are at increased risk, as are people who have longstanding acid reflux problems alone.
http://www.sts.org/doc/4121

Diet:: Diets low in fruits and vegetables, as well as certain minerals and vitamins, particularly vitamins A, C, and riboflavin may increase the risk for esophageal cancer. Overeating, which leads to obesity, increases the risk of the adenocarcinoma type of esophageal cancer. Certain substances in the diet may increase the cancer risk and may explain the high rate of this cancer in certain parts of the world. About 15% of esophageal cancer can be linked to a diet poor in fruits and vegetables. There have been suggestions, as yet unproven, that a diet high in processed meat may also increase the chance of developing esophageal cancer.
http://www.cancer.org/docroot/CRI/content/CRI_2_4_2X_What_are_the_risk_factors_for_esophagus_cancer_12.asp