|
A selection from:
Mayo Clinic on Prostate Health
Continuing from Chapter 7 (go to previous part)
What Are Your Options?
Destroying the cancer with radiation
Radiation treatment uses high-powered X-rays or other radiation
to kill cancer cells. It's generally the preferred treatment if you're
older or in poor health and might have a hard time withstanding
surgery. For cancer confined to the prostate, radiation is often as
effective as surgery for as much as 10 years.
Radiation also is used to treat cancer that has spread outside
your prostate. It can destroy cancerous cells/ shrink tumors and
relieve painful symptoms.
External beam
Radiation is most commonly delivered by a beam from a large
machine placed over your body. Unfortunately, these "external
beams" do more than destroy cancerous cells. They can damage
healthy tissue in the same area.
That's why the first step in radiation therapy is to map out the
areas in your body to receive radiation. Three-dimensional scans
show the location of the prostate and surrounding organs. Computer
imaging software allows a radiation therapist to rotate the picture
in any direction to find the best angles to fire the beams.
Treatments are generally given 5 days a week for about 6 or 7
weeks. Each treatment takes about 15 minutes. However, much of
this is preparation time. The actual length of time you receive
radiation is only about 1 minute. To make sure the beams are
always precisely on the mark, you'll have a body supporter that
will hold you in the same position for each treatment. You'll also be
asked to arrive with a full bladder, which will help hold your
prostate in the same position during each treatment. Ink marks on
your skin will help the radiation therapist hit the same targets each
time. Custom-designed shields cover nearby areas such as your
intestines, anus, rectal wall and urethra, protecting them from
scattered rays.
During the procedure, you'll lie on a table while a machine
known as a linear accelerator moves above you, targeting the
cancer with radiation. The first phase of treatment usually
involves blanketing the entire pelvic region with low doses of
radiation to kill any microscopic cancer cells that have wandered
away from detectable tumors. This continues for about 2 weeks.
During the second phase of treatment, the beams generally
are narrowed and strengthened to target individual tumors.
This gives your intestines and bladder a needed rest from the
radiation. Higher doses of radiation are more effective in
killing the cancer, but they're also more damaging to healthy
tissue. After about 2 weeks of targeting the tumors, you may
receive another 2 weeks or so of blanket radiation throughout
your pelvis.
A new and promising external beam therapy known as three-
dimensional conformal radiation therapy (3-D CRT) uses protons
instead of X-rays to kill the cancer. Protons are parts of atoms that
cause little damage to surrounding tissue but effectively destroy
cells at the end of the beam. This allows your therapist to deliver
stronger doses of beam radiation.
Seed implants
A second radiation method that's gaming popularity uses ultra-
sound-guided needles to inject rice-size radioactive seeds into your
prostate (see illustration). These seeds deliver double the dose of
radiation of external beams, and the seeds cause less damage to
healthy tissue.
|
|
Several small radioactive seeds are inserted into the prostate gland. The seeds emit radiation designed to destroy the cancer.
|
The procedure takes about an hour and is done on an outpatient
basis, with either general anesthesia or spinal (epidural) anesthesia
that numbs the lower portion of your body.
Between 70 and 150 rice-size seeds are inserted throughout your
prostate by way of a needle that passes through the skin of your
perineum, the area between your scrotum and anus. The number of
seeds inserted depends on the size of your prostate. The therapy
generally works better on smaller or moderate-sized prostates.
Radioactive seeds may contain one of several radioactive
substances, depending on the grade of the cancer. Typically, you'll
be given iodine if your Gleason score is less than 6, or the more
potent palladium (puh-LAY-de-um) if your score is higher. These
seeds are left in even after they stop emitting radiation. Other
seeds that contain an even more potent substance, called indium
(i-RID-ee-um), are left in only temporarily.
An ultrasound probe inserted into your rectum guides the
doctor in placing the seeds throughout your prostate, without
missing any areas. A template attached to the outside of the probe
and held up against your perineum guides and steadies the needles
loaded with seeds.
Iodine and palladium seeds generally emit radiation only a few
millimeters beyond where they're implanted. Although this type
of radiation isn't thought to escape your prostate area, doctors
recommend that for the first couple of months you stay at least 6
feet away from children and pregnant women, who are especially
sensitive to radiation. Within a year, all radiation inside the pellets
is generally exhausted.
Because seed implantation is new, its long-term effects are
unknown. But encouraging short-term results suggest that this
could become a common form of prostate cancer therapy in the
decade ahead. According to early studies, radioactive seeds control
cancer growth for 5 years in 90 percent of men, and for 10 years in
85 percent of men. In 2 out of 3 men, the seeds destroy the cancer.
Seed implants generally produce fewer side effects than external
beam radiation. Impotence occurs in about 1 out of 6 men, com-
pared with 1 in 2 for beam radiation. Incontinence is rare.
Are you a candidate for radiation?
• Your cancer can't be cured by surgery because it has spread
outside the prostate.
• Your cancer is confined to the prostate and is a low- or
medium-grade.
• You don't want surgery.
• You expect to live longer than your cancer would allow you
to live.
What are the benefits?
• For cancer confined to the prostate, radiation is nearly as
effective as surgery over a 10-year period.
• The procedure is generally done on an outpatient basis.
With seed implantation, you may need to spend one night in
the hospital.
• Radiation doesn't entail the trauma and recovery associated
with surgery.
What are the disadvantages?
• Radiation can affect your sexual function. Over time, it can
damage the nerves that control erections and the arteries that
carry blood to your penis. Most men don't have problems with
erections or intercourse in the early months after radiation
therapy. But eventually most men suffer some complications.
Only about half of men who had normal sexual function
before radiation retain it after therapy. The percentage is
higher for seed implantation therapy. The younger you are,
the better your chance of retaining the ability to have normal
sexual relations.
• Beam therapy can sap your energy and appetite. Both should
return within a couple of months after treatment.
• Some men have intestinal problems from external beam
therapy, including nausea, diarrhea, rectal bleeding, a burning
feeling around the anus, and a sense that you need to have a
bowel movement. The symptoms generally subside when
the treatments are over. But for about 5 percent of men,
they continue.
• Beam therapy produces urinary problems in approximately 3
out of 4 men. The most common complaints are constantly
feeling as if you have to urinate, blood in your urine, painful
urination with a burning sensation, and urine leakage. About 5
percent of men experience severe symptoms and need to be
hospitalized. Less than 1 percent of those hospitalized require
surgery to correct the problem.
[The chapter continues with "Freezing cancer cells (cryotherapy)"]
|
|
