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Radiation therapy uses high-energy rays or particles to kill
cancer cells. External
beam radiation therapy uses radiation delivered from
outside the body that is focused on the cancer. This is the type of
radiation therapy that has been tried as a treatment for bone cancer.
Most bone cancers are not easily killed by radiation, and high
doses need to be used. These high doses can damage healthy structures
like nerves in the nearby area. This is why radiation therapy does not
play a major role in the treatment of most types of bone tumors,
(except for Ewing tumors, and these are discussed in a separate document).
Often radiation is used to treat bone cancers that are unresectable (they
cannot be completely removed by surgery). Radiation may also be used
after surgery if cancer cells were present in the edges of the tissue
that was removed. Another term for this is positive margins (this was
discussed in the section about surgery).
In this case, radiation may be given to kill any cancer that may have
been left behind. If the cancer comes back after treatment, radiation
can help control symptoms like pain and swelling.
Intensity-modulated radiation therapy (IMRT) is an advanced
form of external beam radiation therapy. With this technique, a
computer matches the radiation beams to the shape of the tumor and can
adjust the intensity (strength) of the beams. The radiation is
delivered to the tumor from several directions to reduce the amount of
radiation that goes though any one area of normal tissue. Altogether,
this makes it possible to reduce radiation damage to normal tissues
while increasing the radiation dose to the cancer.
Proton-beam radiation is a special form of radiation that uses
protons instead of regular X-rays to kill cancer cells. Protons cause
little damage to the tissues they pass through but are very good at
killing cells at the end of their path. This allows a high dose of
radiation be given to the tumor without hurting the normal tissue
around it. Proton beam radiation therapy requires highly specialized
equipment and is currently only offered in certain medical centers.
This form of radiation has been found to be very helpful in treating
skull base chondrosarcomas and chordomas.
Last Medical Review: 07/14/2009
Last Revised: 07/14/2009
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