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Pleural
Mesothelioma
Pleural
mesothelioma is a malignant mesothelioma that spreads within the
chest cavity and sometimes involves the lung.
Asbestos
exposure is the most common risk factor associated with mesothelioma.
Asbestos refers to a family of magnesium-silicate mineral fibers
that have been commonly used for insulation and in the shipbuilding
and construction industries. A history of asbestos exposure is found
in 80 percent of patients who present with mesothelioma. Other factors,
which may promote mesothelioma, include: chronic lung infections,
tuberculous pleuritis, radiation (Thorotrast) and exposure to the
simian virus 40 (SV40) or mineral fibers (Zeolite). Although tobacco
smoking has not been associated with the development of mesotheliomas,
the combination of smoking and asbestos exposure greatly increases
the risk of lung cancer.
In
the United States, 2,000-3,000 patients are diagnosed with malignant
pleural mesothelioma each year.
Mesothelioma affects men more frequently than women and is more
common in white Americans.
The median age of onset of symptoms is 70.
Seven percent of workers exposed to asbestos become affected.
The latent period between exposure to asbestos and the onset of
symptoms can be 20-40 years.
The median survival time is between 4-12 months, depending on the
stage of presentation. The three-year survival is 10 percent and
the overall five-year survival is approximately 5 percent.
The severity of the condition varies from person to person, but
in most cases the onset of Pleural Mesothelioma is usually very
slow with the most common presenting symptom being persistent pain
localized in the chest. Sometimes the pain is accompanied by severe
difficulty in breathing or shortness of breath. Cough, weight loss,
fever and night sweats are less common.
TestingL
Pleural mesothelioma is of two kinds:
1.
diffuse and malignant (cancerous )
2.
localized and benign (non-cancerous.)
Benign
mesotheliomas can often be removed surgically, are generally not
life-threatening, and are not usually related to asbestos exposure.
Malignant mesotheliomas, however, are very serious. Fortunately,
they are rare - about two thousand people are diagnosed with mesothelioma
in the U.S. each year.
The
remainder of this section is about diffuse malignant pleural mesothelioma.
Pleural
mesothelioma is a cancer of the cells that make up the pleura or
lining around the outside of the lungs and inside of the ribs. Its
only known cause in the U.S. is previous exposure to asbestos fibers,
including chrysotile, amosite or crocidolite. Exposure to these
fibers within ten years of a diagnosis of this type of cancer can
be considered as a likely contributing factor in the disease process.
It is the most common type of mesothelioma, accounting for about
75% of all cases.
Mesothelioma
is sometimes diagnosed by coincidence, before there are any symptoms.
For instance, tumors have been discovered through routine chest
x-rays. However, when symptoms occur, they may include shortness
of breath, weakness, weight loss, loss of appetite, chest pains,
lower back pains, persistent coughing, difficulty in swallowing,
alone or in combination. An initial medical examination often shows
a pleural effusion, which means an accumulation of fluid in the
pleural space - the area between the lungs and the chest wall.
The
first step in detecting pleural mesothelioma is, typically, a chest
x-ray or CT scan. This is often followed by a bronchoscopy, using
a viewing scope to look inside the lungs.
The
actual diagnosis usually requires obtaining a piece of tissue through
a biopsy. This could be a needle biopsy, an open biopsy, or through
a tube with a camera (thoracoscopy or chest scope.) If an abnormality
is seen through the camera then a tissue sample can be taken at
the same time, using the same tube. This is a hospital procedure
that requires anesthesia, but is not usually painful. The tissue
sample is tested by a pathologist.
Fluid
build-up from the pleural effusion can generally be seen on a chest
x-ray and heard during a physical examination, but a firm diagnosis
of mesothelioma can only be made through a biopsy and pathological
testing. This is important because there are also benign pleural
effusions and other tumors that have a similar appearance to mesothelioma.
Diagnosing mesothelioma can be quite difficult; it requires special
lab stains, and much experience in understanding them.
The
spread of the tumor over the pleura causes pleural thickening. This
can reduce the flexibility of the pleura and encase the lungs in
an increasingly restrictive girdle. With the lungs restricted, they
get smaller and less functional, and breathing becomes more difficult.
At first a person with mesothelioma may be breathless only when
he or she exercises, but as lung function drops, he or she can become
short of breath even while resting.
The
tumor spreads by direct invasion of surrounding tissue. As it spreads
inward it can compress the lungs. As the tumor spreads outward it
can invade the chest wall and ribs, and this can be extremely painful.
Current
medical science does not know exactly how and why, at a cellular
level, asbestos fibers cause mesothelial cells to become abnormal
(malignant or cancerous.) Thus it is not known whether only one
fiber causes the tumor or whether it takes many fibers. It seems
that asbestos fibers in the pleura can start a tumor as well as
promote its growth; the tumor does not depend on any other processes
for its development.
There
is as yet no known cure for malignant mesothelioma. The prognosis
depends on various factors, including the size and stage of the
tumor, the extent of the tumor, the cell type, and whether or not
the tumor responds to treatment. The Firm has represented many clients
who lived for five to ten years after diagnosis, most of them in
good health for a majority of those years. Some mesothelioma victims
succumb within a few months; the average survival time is about
a year.
Pleural
Mesothelioma Symptoms
chest
pain and pain in the lower back
difficulty breathing
coughing
weight loss
fever
muscle weakness and sensory loss
swelling of the face and arms
hoarseness
coughing up blood
Unfortunately, the early mesothelioma symptoms are often ignored
or mistaken for minor ailments because they are not specific to
the disease.
Therefore,
it is critical to investigate one's exposure to asbestos. While
pain in the lower back or at the side of the chest, shortness of
breath, trouble swallowing, cough, fever, sweating, fatigue and
weight loss may be common to many minor ailments, it is the knowledge
that these mesothelioma symptoms are present in a person with a
high likelihood of asbestos exposure that should raise a red flag.
Mesothelioma
symptoms and signs from mesotheliomas depend upon location of the
mesothelioma, its size and whether it is benign or malignant
Benign forms of the disease are generally asymptomatic
The symptomatology of malignant mesotheliomas is due to tumour growth
resulting in invasion of surrounding structures and/or the production
of fluid (pleural effusion, ascites, or pericardial effusion). Chest
pain may be caused by invasion of the chest wall. Pleural effusion
causes collapse of adjacent lung and shortness of breath
Mesothelioma symptoms of distant spread are possible, but uncommon
since the tumour is usually a local problem and blood borne spread
is uncommon
Patients with more advanced disease may be ill generally with fever,
night sweats and weight loss
Involvement of the membrane around the heart (pericardium) may cause
heart rhythm disturbances
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