Esophageal cancer is a type of cancer that develops in the esophagus, the muscular tube that carries food and liquids from the throat to the stomach. It is relatively uncommon but can be aggressive and challenging to treat. There are two main types: squamous cell carcinoma, which usually occurs in the upper and middle parts of the esophagus, and adenocarcinoma, which typically develops in the lower part of the esophagus.