use of high-energy x-rays or particles to treat cancer is called
radiation therapy. Highly sophisticated equipment is used to aim
and deliver the radiation to the tumors or diseased areas of the
body. Radiation therapy may be used alone, or combined with surgery
Radiation therapy causes changes in the genetic material
of the cells being treated, making it impossible for these cells
to continue to grow and divide. Cancer cells have an abnormally
rapid growth cycle. Because healthy cells grow and divide much more
slowly than cancer cells, normal tissues have more time to recover
from the radiation so are not as adversely affected. Most normal
cells can recover from the effects of radiation and function properly.
The goal of radiation therapy is to damage as many cancer cells
as possible, while limiting harm to nearby healthy tissue.
There are numerous methods of delivering the radiation
that involve different procedures and equipment. The method used
will depend on the part of the body involved and the treatment goal.
For example, certain methods allow the radiation to penetrate more
deeply into the body than can others. Some methods allow it to be
finely controlled to treat small areas. Other techniques are better
suited for treating larger areas. Doctors create highly specific
treatment plans that are tailored to each individual patient.
When is Radiation Therapy used?
More than half of all cancer patients now receive
some type of radiation therapy. Unlike chemotherapy, radiation is
a localized treatment, meaning that only cells in the area being
treated are affected. Radiation may be used in early stage cancers
to cure or control the disease. It can be used before surgery to
shrink the tumor or after surgery to prevent the cancer from coming
back. Radiation may also be used to treat symptoms such as pain
caused by cancer that has spread from the original site.
Radiation therapy may be used to treat almost every
type of solid tumor, including cancers of the brain, breast, gynecological
areas, larynx, lung, pancreas, prostate, skin, spine, stomach, uterus,
or soft tissue sarcomas.
For some types of cancer, radiation may be given to
areas that do not have evidence of cancer to prevent cancer cells
from growing in that area. This approach is called prophylactic
radiation therapy. Radiation can also be given to help reduce symptoms
such as pain from cancer that has spread to the bones or other parts
of the body. This is called palliative radiation therapy.
What are the main types of Radiation Therapy and
what kind will I receive?
The majority of people who are treated with radiation
therapy for cancer receive external beam radiation therapy, which is delivered by a machine outside the body. Internal
radiation therapy (brachytherapy) is the use of
radioactive materials that are placed within the body.
Your doctor will determine what type of radiation
you need and the best technique to use based on the type of cancer
you have, its location, how far into the body the radiation needs
to go, your general health and medical history, whether you will
have other types of cancer treatment, and other factors.