Esophagus Cancer / Oesophagus
What
is the Esophagus?
The esophagus is a hollow tube that transfers food from the throat to the
stomach, that is the
"food tube". The tube starts just below the "epiglottis", the flap that
keeps food from going into
our trachea (air pipe) when we swallow. It ends at where it joins with the
upper portion of the
stomach, called the "cardia". The actual area of coinage is called the
"gastroesophageal junction".
The esophagus is muscular, to help propel food downward with swallowing.
It has a complex array
of nerves ("plexus") that work to coordinate the swallowing motion. The
upper 2/3 of the
esophagus has a inner lining ("mucosa") of a special type of cell, called
"squamous" cells, which are
also found in the mouth and anal region. These cells resist abrasion and
heat and are able to heal
quickly if damaged, say by the sharp edges on food. The lower 1/3 of the
esophagus has an inner
lining of a different type of mucosa called "columnar" cells.
What is
Esophagus Cancer?
The esophagus, like all body tissues, is made up of individual
cells. Normally, cells within the
forming esophagus divide and grow very rapidly in the womb, in early
childhood, and through
puberty. In adulthood, new cells are only formed to replace those which
have died from injury, old
age or disease. The division of cells to produce new ones is under tight
control by the "genes"
within each cell. These genes are made up of DNA, and if it becomes
damaged, the cell may start
dividing out of control. Esophagus cancer starts in a single cell which
has become abnormal. This
cells produces millions, and eventually billions, of copies of itself. The
copies are called "clones".
These clones fail to function as normal esophagus tissue, but instead
divert resources from
healthy cells to fuel their own growth. When there are about 1 billion
cells, they form a clump, or
"tumor" 1/2 inch across. A "tumor" merely means a swelling, it can be
caused by infection,
inflammation, cancer or whatever. If a tumor only grows in it's local area
(even very large) but
does not have the capacity to spread to distant body areas, it is called
"benign" and is not
cancer. If, however, the tumor has the ability to spread to distant body
areas, it is called
"malignant" and this is cancer. The actual process of spread is called
"metastasis", and can occur
to any area of the body.
.
|
