Malignant mesothelioma
is the most serious of all asbestos-related diseases. The primary cause
and risk factor for mesothelioma is exposure to asbestos.
Making a correct mesothelioma diagnosis
is particularly difficult for doctors because the disease often
presents with symptoms that mimic other common ailments. There is no
known cure for mesothelioma, but treatments such as surgery and
chemotherapy have helped to improve the typical mesothelioma prognosis.
Pleural mesothelioma
(affecting the lung’s protective lining in the chest cavity) represents
about three quarters of all mesothelioma incidence. Peritoneal
mesothelioma, which affects the abdominal cavity, and pericardial
mesothelioma, which affects the cardiac cavity, comprise the remainder.
There are three recognized mesothelioma cell-types. Between 50 and
70% of all mesotheliomas are of the epithelial variety. While prognosis
is generally poor, it is considered less aggressive than sarcomatoid
mesothelioma and biphasic mesothelioma, which comprise the remainder of
cell type diagnoses.
The cavities within the body encompassing the chest, abdomen, and
heart are surround by a membrane of cells known as the mesothelium.
Mesothelial cells assist in general organ functions. The mesothelium is
particularly important to organs that are commonly in motion, such as
expansion or contraction of the lungs, stomach, or heart. Lubrication
from the mesothelial cells allows free range of motion within the body.
The mesothelium of the chest, abdomen, and cardiac cavity are called the
pleura, the peritoneum, and the pericardium, respectively. Each of
these groupings of mesothelial cells is extremely critical to the
functions of the body structures which they encompass.
Malignancies (cancerous tumors) occurring within the mesothelial
membranes are known as malignant mesothelioma, or simply mesothelioma.
Benign tumors of the mesothelium are known to occur, but are much more
rare than malignant mesothelial tumors.
While tumors
of the mesothelium were first recognized in the late 18th century, it
was not until the middle of the 20th century that this particular cancer
was studied and examined with more detail. It was at this time when
suspicions of the cancer’s causal relationship with asbestos exposure became more substantiated. A joint research
venture through the Department of Thoracic Surgery at the University of
the Witswater and Johannesburg General Hospital in South Africa
provided the most compelling evidence of the nexus between asbestos
exposure and the development of pleural mesothelioma.
Incidence of mesothelioma is still quite rare, with only 2,500-3000
diagnoses in the United States each year. There was a spike in reported
diagnoses between 1970 and 1984, which has been attributed to the
latency period between diagnosis and the height of industrial exposures,
which occurred roughly 40-60 years prior to this time. Exposure was
common in nearly all industries but was particularly common in the
WWII-era military industrial cycle, including Navy Shipyards.
Although this cancer is much more common in men over the age of 60
(largely attributed to the industrial exposures within male-dominated
industries), mesothelioma in women and children has been described as
well. Mesothelioma causes
for diagnosis in women and children are mainly attributed to secondary
exposure to asbestos, as it was not uncommon for men to bring asbestos
back into the home on their body or clothing if proper cleaning
facilities were not available on site.
Mesothelioma is diagnosed through a comprehensive combination of biopsy and imaging scans.
Mesothelioma
can be a difficult malignancy to diagnose because the
symptoms of the disease closely resemble other respiratory conditions,
and because the pathology can be very difficult to distinguish from
adenocarcinoma of the lung. For this reason, misdiagnosis is not
uncommon in mesothelioma patients. Symptoms of mesothelioma include
chest pain, chronic cough, effusions of the chest and abdomen, and the
presence of blood in lung fluid.
Diagnostic surgeries, including a biopsy, will typically be required
to determine the type of malignant cells that are present in the body.
Typically a body imaging scan, including a magnetic resonance image
(MRI), computer topography (CT scan), and/or positron emission
tomography (PET), will be required to determine the extent and location
of the disease.
While mesothelioma is typically advanced at diagnosis, treatment options are available.
Mesothelioma,
while certainly an aggressive disease, is a manageable malignancy.
While there is no cure for the cancer, mesothelioma treatment
options may potentially include surgery, chemotherapy, and radiation
therapy. A combination of Alimta® and Cisplatin is currently the only
FDA approved chemotherapy regimen, though several clinical trials are
currently in progress utilizing other drugs including Gemcitabine and
Onconase, that may lead to new treatment options that provide a benefit
for patients.
Radiation therapy is also utilized, but typically in conjunction with
other treatment methods like surgery and chemotherapy. Surgical
resection of mesothelioma is possible in early-stage-diagnosed patients.
Diagnostic and palliative procedures such as thoracentesis and
pleurodesis are also commonly performed in patients with malignant
mesothelioma in order to minimize cancer-related symptoms.
Alternative therapies have also been used effectively by many
mesothelioma patients to assist in managing symptoms of the disease and
conventional treatments.
Mesothelioma is caused by exposure to asbestos.
Mesothelioma is primarily caused by exposure to asbestos, though
cases have been documented in children or other individuals with no
asbestos history. Asbestos is a microscopic and naturally occurring
mineral that lodges in the pleural lining of the lungs and the
peritoneal lining of the abdominal cavity. In most cases, several years
will pass (up to 60) before mesothelioma develops in those who had been
exposed to asbestos.
