Spread
and Staging
Because mesothelioma becomes
more deadly the longer it is left
untreated, the best chance for
beating the disease (or at least
keeping it at bay for as long
as possible) is to catch it very
early. The course of the disease
is divided into four stages, which
are based on how far the cancer
has spread.
Cancer spreads when cells break
away from the primary tumor and
enter the bloodstream or the lymphatic
system. When this happens, it
is called metastasis. Metastatic
cancer can spread to any area
of the body and create new tumors,
but new tumors are most likely
to develop near the site of the
primary infection. Metastatic
tumors are made up of cancerous
cells from the organ in which
the primary tumor originated,
no matter where else in the body
they form. For example, if mesothelioma
spreads to the lung, the tumor
in the lung will be made of cancerous
mesothelium, not lung tissue.
This is one way that doctors can
tell where the cancer originated.
Since metastatic cancer travels
partly through the lymphatic system,
it is very common for it to spread
to the lymph nodes, especially
lymph nodes close to the site
of the primary tumor. The lymphatic
system is part of the immune system,
and branches throughout the body
much like blood vessels, carrying
infection-fighting cells. Lymph
nodes are small organs located
along this network of vessels,
which act as filters, collecting
and destroying unwelcome foreign
matter.
At this time, staging only exists
for pleural mesothelioma. This
is because it is so much more
common than peritoneal mesothelioma.
The lower the stage number, the
better the prognosis. Beyond Stage
I, there is little hope of a complete
recovery.
At Stage I, mesothelioma affects
the inner lining of the chest
on one side of the body, and may
have spread to the outer lining
of the lung in a few small places,
but has not yet spread to other
organs or the lymph nodes.
At Stage II, mesothelioma has
spread more extensively into the
outer lining of the lung, or even
into the lung itself. It may also
have spread to the diaphragm,
but has still not reached the
lymph nodes or distant sites.
At Stage III, mesothelioma may
have spread to the lymph nodes
near the tumor, but would not
have spread as far as the collarbone.
It may also have spread into the
chest wall, or even into the outer
layer covering the heart, but
has not yet spread to the other
side of the chest or to distant
sites.
At Stage IV, mesothelioma may
have spread into the muscle, the
ribs, the trachea, the esophagus,
the spine, to the other side of
the chest, or into the heart itself.
Mesothelioma is also classified
at Stage IV if it affects lymph
nodes near the collarbone or has
spread to distant sites.
Staging the disease is an important
step, which can aid in the development
of a treatment plan appropriate
for the individual case. Even
if there is no hope of a cure,
treatment can still extend life
expectancy and provide pain relief.
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