GPS for the Body Sometimes Needed for a Moving
Prostate During Radiation Therapy
Prostate can move during a treatment session and can
make delivering radiation safely to the tumor a challenge
By
Constantine A. Mantz, MD
Jan. 21, 2009 - Prostate cancer is the second
leading cause of cancer death for men after lung cancer. According to
the Prostate Cancer Foundation, prostate cancer is treatable and highly
curable if the disease is detected early.
Beacon electromagnetic
transponders implanted in prostate
Radiation therapy is a standard treatment option
for prostate cancer. Cure rates are similar to those who opt for
surgery. However, patients who undergo radiation are spared the risk of
surgery, such as bleeding and infection. Furthermore, most patients
undergoing radiation therapy are able to enjoy their normal daily
activities during treatment.
For those patients who opt for radiation therapy,
it is important for them to be aware that the prostate can move during a
treatment session and can make delivering radiation safely to the tumor
a challenge for the radiation oncologist. In clinical studies, the
prostate was seen to move unpredictably and variably, patient to patient
and minute to minute. This prostate movement is due to normal bodily
functions, such as gas passage through the rectum, urine filling the
bladder and breathing.
Conventional radiation treatment methods do not
allow for continuous monitoring of the prostate's position in real-time
and can not predict which way or how much organs will move. If the
prostate’s position can be monitored throughout treatment, then the
radiation may be more safely and accurately delivered to the cancer,
maximizing the treatment’s benefits and minimizes potential damage to
nearby tissues or organs.
Fortunately, several leading hospitals throughout
the U.S., including 21 Century Oncology in Cape Coral, Fla., have
adopted a new technology called “GPS for the Body®” that specifically
tracks prostate motion in prostate cancer patients and enables more
accurate delivery of radiation.
The system allows radiation oncologists to detect
very slight prostate movement almost instantaneously so that extremely
accurate radiation therapy can be delivered. These movements are
signaled by three electromagnetic Beacon® transponders -each the size of
a grain of rice - which are permanently implanted within the patient’s
prostate gland.
These transponders send electromagnetic waves that
allow physicians to pinpoint precisely the location of the prostate as
it moves during treatment. If necessary, the physician can pause
treatment to re-adjust the patient, thereby avoiding potential damage to
the nearby rectum and bladder.
Current methods for aligning treatment involve
imaging the prostate – using implanted gold markers and X-ray images or
ultrasound scans – before each radiation treatment session. However,
current methods such as these cannot account for the prostate’s position
once the treatment begins. GPS for the Body, also known as the Calypso®
4D Localization System™, provides continuous real-time information about
the prostate’s position before and during treatment.
My patients who have undergone radiation using this
system find confidence and reassurance in knowing that a GPS for the
Body® is providing guidance to manage any possible prostate motion
during the delivery of radiation therapy. Early stage prostate cancer is
a very curable disease, and this technology allows me to deliver
radiation therapy accurately to maximize the opportunity for cure and
minimize any chance of complication and side effects. GPS for the Body®
suits our goals of curing the patient’s cancer, while maintaining an
excellent quality of life.
About Author
Dr. Constantine Mantz is a practicing Radiation
Oncologist in Cape Coral, Fla. For an appointment, please call (239)
772-3202 or visit: www.21centuryoncology.com.
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