Radiation Therapy for Prostate Cancer
Facts
About Prostate Cancer
Prostate cancer is the most
common malignancy in American men.
- In 2003, more than 220,000 men were diagnosed as having prostate
cancer, making it the number one type of cancer in men.
- Nearly 29,000 men died from prostate cancer in 2003.
- More than 75 percent of prostate cancer is diagnosed in men
over age 65.
Risk
Factors For Prostate Cancer
Incidence of prostate cancer
increases with age.
- Median age at diagnosis in Caucasian males is 71.
- African-American men have the highest incidence of prostate
cancer in the world.
- Heredity accounts for 5 to 10 percent of cases.
Screening
For Prostate Cancer
According to the American
Cancer Society, men aged 50 or older should be offered a digital
rectal exam (DRE) and a PSA blood test. However, it is a good idea
to visit your doctor earlier to establish a baseline PSA level so
you can monitor changes.
- Prostate specific antigen (PSA) is a valuable marker for prostate
cancer although BPH or infection may also cause a rise in PSA.
- Normal range is 0-4, however, a PSA above 3 in men younger than
60 may be considered abnormal.
- African-American men and men with a family history of prostate
cancer should be examined beginning at an earlier age.
Diagnosing
Prostate Cancer
Prostate cancer is most often
diagnosed through a blood test measuring the amount of prostate
specific antigens (PSA) in the body. However, signs and symptoms
of prostate cancer can include:
- Changes in urinary flow: Frequency, urgency, hesitancy.
- Frequent nighttime urination.
- Painful urination.
- Blood in urine.
Other conditions that may
cause these symptoms include an enlarged prostate (benign prostatic
hypertrophy or BPH) or infection.
Radiation
Therapy Options for Treating Prostate Cancer
After a diagnosis of prostate
cancer has been established with a biopsy, the patient should discuss
the treatment options with a radiation oncologist and a urologist.
Radiation therapy treatment options to cure prostate cancer include:
- External beam radiotherapy.
- Prostate brachytherapy.
External
Beam Radiation Therapy
External beam radiation therapy
involves a series of daily outpatient treatments to accurately deliver
radiation to the prostate.
There are two principal methods
for delivering external beam radiation.
- 3-dimensional conformal radiotherapy (3D-CRT) combines multiple
radiation treatment fields to deliver precise doses of radiation
to the prostate. Tailoring each of the radiation beams to accurately
focus on the patient's tumor allows coverage of the prostate cancer
while at the same time keeping radiation away from nearby organs
such as the bladder or rectum.
- Intensity modulated radiation therapy (IMRT) is the most recent
advance in the delivery of radiation. IMRT improves on 3D-CRT
by modifying the intensity of the radiation within each of the
radiation beams. This technique allows more precise adjustment
of radiation doses to the tissues within the target area, potentially
allowing an increased radiation dose to the prostate and reduced
doses to nearby normal tissues. Higher doses to the prostate translate
into a greater chance for cure, while lower doses to surrounding
organs mean fewer side effects.
Both types of external beam
radiation therapy are acceptable treatment; IMRT offers advantages
for some but not all prostate cancer patients. With either type
of therapy, painless radiation treatments are delivered in a series
of daily sessions, each under half-hour in duration, Monday through
Friday for seven to ten weeks overall.
Potential side effects, including
fatigue, increased frequency or discomfort of urination, and loose
stools, typically resolve within a few weeks after completing treatments.
Impotence is also a potential side effect of any treatment for prostate
cancer. However, many patients who receive radiation therapy for
prostate cancer are able to maintain sexual function. Prostate
Brachytherapy
Prostate brachytherapy, better
known as a seed implant, is often done in the operating room.
There are two methods of
delivering internal radiation for prostate cancer:
- Permanent seed implants.
- High-dose rate temporary seed implants.
These treatments are designed
to deliver a very high dose of radiation to the tumor by inserting
radioactive seeds directly into the prostate gland under ultrasound
guidance while the patient is under anesthesia. Isotopes of iodine
or palladium are most commonly used. The seeds are approximately
four millimeters long and less than a millimeter in diameter. In
certain situations, both prostate brachytherapy and external radiation
may be recommended to combat the tumor.
The side effects from seed
implants are similar to those experienced with external beam radiotherapy.
Patients usually experience urinary frequency and discomfort in
urination. These effects may be lessened with medication and usually
dissipate over the course of three to six months. Proton
Beam Therapy
A Proton Beam Machine will
be installed in Robert Wood Johnson University Hospital in near
future. In a few parts of the country, proton beam therapy is being
used to treat prostate cancer.
Proton therapy is administered
much the same way as external beam therapy, but it uses protons
rather than x-rays to irradiate cancer cells. Hormone
Therapy
Certain patients may benefit
from hormone therapy in addition to radiation. In some patients,
hormone therapy works with radiation therapy to improve cure rates.
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