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What is esophageal cancer and its Types?


Although its incidence is not very high, esophageal cancer is one of the most severe cancers since it is usually diagnosed in advanced stages, which complicates its treatment. Know the different ways to approach it.

The esophageal cancer is tumor frequency 8th and 6th in mortality. It is a first-class health problem since, despite its low incidence, it has a high mortality rate (close to 90% of all patients). More than half of patients have been diagnosed in locally advanced or metastatic stages (unresectable).

What is the esophagus like?

The esophagus is a straight tube that connects the pharynx with the stomach. It is about 25 cm in humans, and its structure shows the distinct layers of the digestive tract, which are (from inside to outside): mucosa, submucosa, muscular, and severe (or adventitia).

The mucosa is formed by a flat stratified epithelium, normally non-keratinized (without keratin, like the epidermis). Simultaneously, the submucosa is a dense connective tissue with a large number of elastic fibers that allow it to dilate when the food bolus passes. The lumen (inside) of the esophagus comprises numerous longitudinal folds of the mucosa and submucosa.

Types of esophageal cancer and incidence

90% of esophageal cancers are squamous histology (usually located in the upper and middle third) or adenocarcinomas (in the lower third). The remaining 10% are of other types such as mixed (adenosquamous), sarcomas, microcytic, etc.

Its incidence by race and country is highly variable. Until the 1960s, 90% of esophageal tumors were squamous, and adenocarcinomas were so rare that their existence was even doubted.

While the incidence of squamous cells has not changed or is decreasing due to the decrease in the causes that produce it ( alcohol and tobacco), adenocarcinomas have increased in the Western world, probably in proportion to the increase in gastroesophageal reflux (associated with obesity ) and subsequent development of Barrett's esophagus (Change or substitution –metaplasia– of the cells that usually line the final portion of the esophagus with others that are more resistant to stomach acidity).

Patients with recurrent reflux symptoms have a risk of developing adenocarcinoma of the esophagus seven times higher and up to 40 times if the symptoms are severe in addition to being prolonged. Unlike squamous cell carcinoma, adenocarcinoma is not related to alcohol consumption (although related to smoking).

Other risk factors for esophageal cancer

Certain socioeconomic factors can also influence esophageal cancer development since it has been seen an increase in its incidence in diets lacking in fruits and vegetables in economically depressed regions.

The habit of drinking very hot beverages ( tea or coffee ) in regions such as the Middle East and China has also been linked to a higher incidence of esophageal cancer, as well as eating foods rich in nitrous (certain pickled vegetables) and other foods (mushroom producers), or some nuts prepared in those endemic areas.

Abuse in the intake of red meat, low levels of selenium, zinc, or folic acid in the diet, history of esophageal achalasia (esophageal motility disorder that leads to the dilation of the esophagus or megaesophagus), caustic scars (due to ingestion of bleach, acids, etc.), a history of gastrectomy, atrophic gastritis is other risk factors for the development of esophageal cancer.

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