The esophagus (sometimes called the "food pipe") is a muscular tube about 10 inches long through which food passes from the throat to the stomach.
Cancer of the esophagus occurs when the cells of the esophagus begin growing abnormally. This type of cancer usually forms in the tissues lining the esophagus. There are two main types: squamous cell carcinoma and adenocarcinoma.
Squamous Cell Carcinoma
This type of cancer grows in the flat cells (squamous cells) of the inside layer of the lining of the esophagus and causes less than half of all esophageal cancers.
Cancers that start in the glandular cells—which make and release mucus and other fluids—are called adenocarcinomas. Glandular cells are not normally part of the inner lining of the esophagus, but acid reflux disease can cause squamous cells to change into glandular cells.
Acid reflux disease is often caused by a weak lower esophageal sphincter (LES), which is a muscle located between your stomach and the bottom of your esophagus. When a weak LES doesn't close completely, stomach acid backs up into the esophagus. Often experienced as heartburn, this condition is known as gastroesophageal reflux disease (GERD).
Over the long-term, GERD can cause the squamous cells to become like glandular cells, leading to a disease known as Barrett's esophagus. If left untreated, Barrett's esophagus can slowly progress to esophageal cancer.
People with Barrett's esophagus are at higher risk for developing esophageal cancer and should have their conditioned closely monitored by a doctor.