NCCN Guidelines for Patients
: Malignant Pleural Mesothelioma
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Part 2: Am I at risk?
Asbestos is a group of minerals made of tiny fibers. It is
strong, flexible, and resistant to heat and fire. Because
of these traits, asbestos has been used in housing and
commercial products, such as roofing and brake pads.
Asbestos is the only
Asbestos can break into tiny pieces
that may be breathed in or swallowed. The asbestos
pieces can then get trapped in the lungs and remain
there for years. How asbestos gets into the pleura (the
tissue lining around the lungs) and causes normal cells
to become cancer cells isn’t fully known. It often takes
20 to 40 years after having had contact with asbestos
for mesothelioma to develop. There are no studies that
clearly show the length of time exposed to asbestos that
is needed to increase the risk for mesothelioma.
Asbestos is divided into two main groups: serpentine
and amphibole asbestos. Serpentine is made of long,
curly fibers, whereas amphibole is made of straight,
needle-like fibers. There are different types of asbestos
within each main group, but the most commonly used
include chrysotile, crocidolite, and amosite.
Of these three, chrysotile is the most widely used
to make products. Chrysotile is a type of serpentine
asbestos. Its long, curly fibers make it less likely to
break into pieces and cause mesothelioma. Crocidolite
and amosite are types of amphibole asbestos. They are
used less frequently because their straight, needle-like
fibers are more brittle and likely to break, or fragment.
However, because they fragment, they are more likely to
be breathed in or swallowed and cause mesothelioma.
A gene mutation is an abnormal change in the
instructions for making and controlling cells. Recent
studies show that having a mutation in the
may further increase the risk for mesothelioma in people
who have been exposed to asbestos. This gene mutation
can be passed down from parents to children.
Some patients with mesothelioma have had no clear
exposure to asbestos. This suggests that there may be
other causes of the disease. Prior radiation therapy, such
as that given for Hodgkin’s lymphoma, may be a cause.