| - Prostate Cancer Treatment: Radiation -
Radiation therapy uses high-energy, either aimed
from a machine or emitted by radioactive seeds implanted
in the prostate, to damage cancer cells beyond repair. When prostate cancer
is localized, radiation therapy is a primary treatment option along with surgery. External beam radiation therapy is also commonly
used to treat men with regional disease, whose cancers have
spread too widely in the pelvis to be removed surgically.
In men with advanced disease, radiation therapy can help
to shrink tumors and relieve pain.
External Beam Radiation Therapy (XRT)
External beam radiation therapy generally involves
treatments 5 days a week for 6 or 7 weeks. Each session lasts just a few minutes.
In many cases, if the tumor is large, hormonal therapy may
be started at the time of radiation therapy and continued
for several years. The primary target is the prostate gland
itself. In addition, the seminal vesicles may be irradiated
(since they are a relatively common site of cancer spread).
Radiating the lymph nodes in the pelvis, once common practice,
has not proven to produce any long-term benefits for most
patients, but it may be necessary in certain circumstances.
Radioactive Seed Implantation (Brachytherapy)
Radiation can also be delivered to the prostate by implanting many tiny radioactive seeds directly into
the prostate gland. This approach, known as interstitial
implantation or brachytherapy, has the advantage of delivering
a high dose of radiation to tissues in the immediate area,
while minimizing damage to adjacent tissues such as the rectum
and bladder.
As practiced today, brachytherapy relies
on ultrasound imaging much the same way prostate cryotherapy does. The placement of needles through the skin of the perineum is guided by the images on the screen. Seeds made of
radioactive palladium or iodine are delivered through the
needles into the prostate, according to a customized pattern—using
sophisticated computer programs—to conform to the
shape and size of each man's prostate.
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