NCCN Guidelines for Patients
Malignant Pleural Mesothelioma, Version 1.2016
What are the risk factors?
What are the risk factors?
A risk factor is something that increases the chance
of getting a disease. Risk factors can be activities
that people do, things in the environment, or traits
passed down from parents to children through genes.
Doctors know some risk factors are linked to specific
cancer types. When it comes to mesothelioma,
exposure to asbestos is the only known risk factor.
Asbetos is the primary cause
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 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
Asbestos is divided into two main groups:
Serpentine is made of long, curly fibers.
Amphibole is made of straight, needle-like
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
Other possible risk factors
Some patients with mesothelioma have had no clear
exposure to asbestos. This suggests that there may
be other causes of the disease. A gene mutation is
an abnormal change in the instructions for making
and controlling cells. Recent studies show that
having a mutation in the
gene may increase
the risk for mesothelioma. However, the cause-and-
effect relationship between asbestos exposure and
mutation is uncertain. This gene mutation
can rarely be passed down from parents to children.
Prior radiation therapy, such as that given for
Hodgkin lymphoma, may also be a cause.
Smoking does not appear to put you at risk for
mesothelioma. If you smoke and have contact with
asbestos, you have an increased risk for lung cancer.
If you are diagnosed with mestothelioma and smoke,
it is suggested you quit since smoking may interfere
with cancer treatment. Read more about smoking in