There is not a sure way to prevent esophageal cancer, but you can lower certain risk factors, decreasing your chance of developing cancer of the esophagus. Among the controllable risk factors are tobacco and alcohol consumption. If you smoke, STOP. And limit the number of alcoholic beverages you consume on a regular basis.
http://www.mercyorthopedics.org/cm/content/prevention_esophageal.asp
Esophageal Cancer Prevention & Detection