Esophageal cancer is one of the uncommon cancer types that starts in the esophagus — a long, muscular and hollow tube connecting mouth and stomach.
The primary function of the esophagus is to help move the food once swallowed from back of the throat to stomach so that it’s finally digested.
While the upper esophageal sphincter (UES) helps in performing functions such as breathing, eating, vomiting and preventing the food and secretions from entering the windpipe, the lower esophageal sphincter (LES), on the other hand, performs a function of preventing stomach contents including acids from flowing backwards into the esophagus.
Esophageal Cancer – Definition
Esophageal cancer is characterized by abnormal, uncontrolled cellular growth that forms in tissues and cells of the esophagus. This cancer can start anywhere along the esophagus and invade surrounding tissues. It may also spread (metastasize) to the distant bodily tissues or organs via the bloodstream, lymphatic system, or other means.
Esophageal cancer usually begins in the inner layer of the esophagus wall, and it continues to grow outwards towards the other layers.
The wall of the esophagus has multiple layers; namely, mucosa, submucosa, muscularis propria and adventitia. While mucosa is the innermost layer, adventitia is the outermost layer of esophagus.
What are the main causes of cancer of esophagus?
Although the exact cause of esophageal cancer is still not known, there are certain risk factors that increase the likelihood of causing esophageal cancer.
As with most cancer types, occurrence of mutations or damage to the DNA (Deoxyribonucleic acid; genes) in cells which leads to cancer is said to be one of the causes, though the exact reason as to why normal cells become cancerous is still not known.
It’s only a very small number of esophageal cancers that are caused by inherited gene mutations. Apart from such inherited mutations, acquired gene mutations are largely responsible for causing the condition. Such mutations happen during a person’s lifetime and are not passed on to their children.
Other than that, genetic and environmental factors too play a crucial role in the development of esophageal cancer in certain people. This includes excessive use of tobacco or alcohol as it causes squamous cell cancer of the esophagus. And when both are consumed together, the risk of this type of cancer increases.
Smoking increases the risk of adenocarcinoma as well.