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Patients who pursue temporary brachytherapy
as their prostate
cancer treatment will undergo a planning stage.
A radiation oncologist, an urologist, and a physics
team will carefully plan the minimally invasive surgery
to ensure the seed is put in the correct location. The
radiation oncologist and the physics team design a map
for the flexible plastic catheters. The oncologist uses
the transrectal ultraound (TRUS) to take pictures of
the prostate and surrounding organs every five millimeters.
After imaging, which takes about 15 minutes, the oncologist
writes a prescription for the amount of radiation needed,
then gives the prescription and images to the physics
team. The physics team arranges a pattern for the small
and flexible catheters that will be inserted into the
prostate gland.
During the minimally invasive surgery,
only one iridium-194
seed is used. The seed is inserted through the catheters
one at a time. Because they are flexible plastic instead
of rigid steel, the catheters can be guided to wherever
the medical team plans for them to go. An urologist
can maneuver around an enlarged prostate gland or an
interfering pubic
arch. Patients therefore do not need
to undergo neoadjuvant hormone
therapy.
Before the procedure patients usually
start antibiotics to help prevent an infection and undergo
mechanical bowel preparation. Not eating anything after
midnight or taking enemas or laxatives are all examples
of bowel preparation. Fecal matter could interfere with
the treatment. Before beginning, an anesthesiologist
puts a patients under general or spinal anesthesia that
numbs him from the waist down. Patients who remain awake
should not laugh, cough, or talk because these activities
could upset the precision of the treatment.
Minimally Invasive Surgery
for Prostate Cancer
A hospital stay for temporary brachytherapy lasts 24
to 36 hours because a patient receives two or three
treatments. He is placed in the lithotomy position,
meaning his feet are put into stirrups and his legs
are lifted to 90 degrees. This position gives the doctor
a clear view of the perineum,
which is cleaned and then possibly shaved according
to the practice of the center. The doctor inserts an
ultrasound probe into the rectum
and attaches it to a stabilizing device which holds
the tool for the duration of the treatment.
Some doctors will hold the perineal
template in their non-dominant hand while they are inserting
the catheters. The doctor uses the perineal template
to guide the percutaneous insertion of 20 to 49 catheters.
The number of catheters depends largely on the size
of the prostate gland. The free-hand technique, in addition
to the malleability of the catheters, allows the doctor
to maneuver around the pubic arch and place the catheters
according to the plan. The doctor then fixes the perineal
template to the stabilizing device.
A computer inserts a single iridium-194
seed into a catheter and leaves the seed there for 5
to 15 minutes. The computer repeats this process with
each of the catheters. After finishing, the catheters
are left in place and the patient is transported to
a hospital room. He will undergo 1 or 2 more sessions
before his prostate cancer treatment is complete. The
entire procedure takes a day or two. In between treatments,
patients rest in a hospital bed. They may roll from
side to side, but they cannot sit up without breaking
a catheter.
Temporary brachytherapy leaves no
radioactive seeds inside the body, therefore, there
is no risk for seed migration. Some researchers are
also finding that high dose rate brachytherapy has a
lower incidence of cold and hot spots. A cold spot occurs
when an area is not adequately irradiated, while a hot
spot occurs when an area is over-irradiated. Cold spots
may lead to prostate cancer recurrence while hot spots
may lead to damage of the rectum or bladder.
Post-operative Seed Implants
Most patients move around freely as soon as the catheters
are removed and the anesthesia wears off. Doctors will
prescribe antibiotics and possibly an alpha-blocker,
which relaxes the neck of the bladder and decreases
the severity of urinary side effects. Patients may also
take over-the-counter medications to alleviate soreness
in the perineum. Some patients will use ice packs the
next day or two to reduce swelling. |
