Cancer Care: Areas of Expertise
Prostate Cancer:
Radioactive Seed Implants (Monotherapy)
Radioactive seed implantation involves the precise
placement of small, rice-sized radioactive seeds directly into the
prostate gland using transrectal ultrasound guidance. Two radiation
isotopes are commonly used: 1) Palladium-103 (Pd-103) which has
a half-life of 17 days and emits most of the radiation over two
months; and 2) Iodine-125 (I125) which has a half-life of 60 days
and emits most of its radiation over six months. During these time
periods, the
prostate gland receives continuous irradiation. When a seed implant
is performed alone, without external beam radiation, it is called
monotherapy.
Procedure Preparation
Approximately two weeks prior to implantation, the patient will have
routine blood tests and may also undergo an EKG, chest X-ray
and a urinalysis. If there is any history of heart disease or other
significant medical problems such as hepatitis, diabetes, or lung
disease, you should let your doctors know as soon as possible,
as it may be necessary to get clearance from your internist, cardiologist,
or other medical specialists. Sometimes this can take several weeks.
If you have any history of a heart attack or angina, a thallium
stress test may be required.
All anti-inflammatory
medications, such as aspirin, Motrin, Advil, ibuprofen, Aleve, or
naprosyn must be discontinued at least two weeks prior to the implant.
It is OK to take Tylenol for pain. If you are on Coumadin®, this must
be discontinued five to seven days prior to the implant, under the
direct supervision of the physician who prescribed this medication.
In many cases another medication is substituted for Coumadin.
Prior to the implant, you will
be instructed to take laxatives or enemas (a bowel prep). It is very
important for the rectum to be empty at the time of seed placement.
Both stool and gas will interfere with ultrasound imaging of the
prostate. If your physician has not given you these instructions,
please let us know several days before the implant.
Implant Planning
Before an implant can be performed, the patient must undergo a volume
study. This study involves placing a transrectal ultrasound into
the rectum and making measurements and taking pictures. Unlike the biopsy
no needles are used. This procedure takes a few minutes. This measurement
will provide the necessary information so that the radiation oncologist
can order the proper number of seeds for the seed implant.
The Implant Procedure
The prostate seed implant is performed by a urologist and radiation
oncologist, both of who have undergone special training in prostate
seed implantation. When you arrive at the hospital, you should
have already have completed your bowel prep. After completing your
registration you will go to the pre-op area and will meet with
the anesthesiologist to discuss the kind of anesthesia that is
most appropriate for you.
When
it is time to start the procedure, you will be taken to an operating
room that is specially equipped for urological procedures. Anesthesia
will be administered. A Foley catheter will be placed into the bladder.
The skin of the perineum, an area located between the rectum and
scrotum, will be cleaned with an antibacterial solution. In order
to further reduce the risk of infection, the hair may be shaved from
this area.
The
implant procedure is initiated by placing the ultrasound probe into
the rectum and attaching it to a stabilization unit and the seed
implantation system. The next step involves a careful mapping of
the prostate gland. This allows physicians to determine how many
seeds are required and where the seeds are going to be placed.
During the course of
the implant, approximately 16 to 26 needles are inserted through
the perineum into the prostate. The implant needles are easily seen
on the ultrasound screen. This allows precise placement into specific
locations within the prostate under direct visualization.
A template, or guidance system, is attached to the ultrasound
probe outside the patient next to the perineum. The template is used to
guide the needles into precise locations in the prostate as is called for
by the plan. The template (FIGURE 1) has a series of holes, coded A through
G horizontally and 1 through 6 vertically. The dots correspond
to holes in the template, which are used to guide the implant needles into
precise locations within the prostate.

The template coordinate grid seen above is activated
so that it appears on the ultrasound screen (Figure 2). The prostate is
aligned so that it is superimposed onto the template grid in such a way
that the D row is centered in the central portion of the prostate and the
1 row is aligned along the back edge of the prostate.

Example of how the template is used in a prostate implant:
If the implant is to start at the location of “F2” on the grid,
the needle is placed through the “F2” aperture in the template
and, under the guidance of the ultrasound, is directed into the prostate
at the“F2” location as seen on the ultrasound screen. If the
needle does not hit the “F2” coordinate, it can be easily steered
into the proper location. Depending upon the size of the prostate,
16-26 needles are used to implant 60-140 seeds.
Once the procedure
is completed, the patient is transferred to the recovery room. After
the anesthesia has worn off, you will be discharged. In
most cases, the Foley catheter is removed prior to discharge.
Follow-up Procedure
You will be scheduled to have a CT scan of the prostate so that
computerized dose calculations can be performed. This will allow
your radiation oncologist to evaluate the actual dose delivered
to the prostate gland as a result of the implant. These calculations
are called post-implant dosimetry. The post-implant CT scan does
not involve the injection of any dyes or contrast. You will not
be required to drink any barium or use any laxatives or enemas.
This test only takes about five minutes.
As part of your follow-up care, you will be instructed
to see both your urologist and radiation oncologist. They will
help you to get through the side effects as comfortably as possible.
After three months they will perform routine DRE’s.
The first PSA will be drawn
about three months after the implant. Bone scans, CT scans, and MRI
scans are not part of the routine follow-up. They may be ordered
if your PSA rises.
Side Effects of Seed Implant Therapy
- Perineal Symptoms
Side effects of seed therapy vary widely from one patient
to the next. Most patients experience tenderness in the perineum
for several days following the implant. Bruising and discoloration
can extend into the scrotum. This should not be alarming. The perineal
discomfort is usually mild to moderate and can be managed with Tylenol,
Aleve, or ibuprofen. These medications are okay to take after an
implant.
- Urinary Symptoms
In the first 24 to 48 hours after the implant, there may be moderate
to severe burning on urination and the urinary stream may be
very weak. About 5 percent of the patients find it impossible
to urinate at night and must return to the hospital emergency
room for placement of a Foley catheter. If urinary blockage
occurs during the day, please contact your urologist. He or
she may be available to place a catheter in their office.
- For
several weeks or months after the implant patients may experience
urinary urgency, frequency and irritation. These symptoms can
be mild, moderate or severe and tend to be worse at night. Initially,
most men find that they get up at night to urinate two to four
times more than they did before the implant. Men who have burning
on urination usually report that this discomfort is felt on the
tip of the penis. This is not the result of any injury to the
penis, but rather these sensations are being referred to the
penis from the prostate.
- Medications called alpha-blockers (Flomax, Hytrin
or Carduria) are particularly helpful in relieving these symptoms. These
medications help the prostate to relax, allowing the urine to pass
more freely through the swollen and inflamed gland. Anti-inflammatory
medications such as Aleve or ibuprofen can also be very helpful.
Occasionally, there is bladder irritation. In that case, patients
may benefit from Pyridium, which numbs the bladder.
- Urinary urgency can
be rather severe for a month or two after the implant, and if not careful,
an accident might occur. In order to avoid urinary leakage it is
best to set-up a schedule and void every hour while awake. Severe
urgency is often triggered by standing up or touching water. So
be prepared to rush to the bathroom in those situations. Be prepared
to quickly find a bathroom when you hop out of the car. If you
have been sitting in a meeting at work for more than an hour, be
prepared to rush to the bathroom when you stand up. Never pass up the
opportunity to use the men’s
room.
- How long do the urinary
symptoms last?
The urinary symptoms can last for many months. They tend to last
longer with I-125 seeds than with Pd-103 seeds. However, at some
point, usually six to eight weeks after the implant, the symptoms
will begin to improve. By three months, most men who have a Pd103
prostate seed implant, will say that their urinary function is 90
percent back to normal, and that they are getting up at night one
extra time or the same number of times as they did before the implant.
Urinary burning may last only a few days, however, as the radiation
dose builds up in the prostate, the burning sometimes returns between
the third and sixth week after the procedure. If this is the case,
the burning usually resolves by three months. The last symptom to
go away is the weak stream. The strength of the stream is usually
pretty good by three months, but it may take another couple of months
for the stream to fully return to normal. Alpha-blockers are usually
discontinued between the third and fourth month. Occasionally the
urinary stream never fully recovers and patients may stay on long-term
alpha-blocker medication.
- Urination at night
The most common urinary complaint is frequent urination at night,
which can significantly interfere with sleep. Patients report that
they will get up many times to urinate, but that the stream is
weak and that they cannot empty their bladder. This will cause
them to get up again soon thereafter. Sometimes patients are unable to
get their stream started for five to ten minutes. Infrequently
patients have severe burning and say that urination feels like they are “peeing
through razor blades.” Alpha-blockers
are very helpful for nighttime symptoms, and unless a patient
is instructed otherwise, it is best to take these medications about
one hour after dinner. It is also helpful to avoid fluids in the
evening to reduce urination frequency during the night.
- Rectal Symptoms
Some patients occasionally experience rectal urgency, frequency,
discomfort, or bleeding. Bleeding is more likely to occur in patients
with hemorrhoids. Ointments or suppositories can help with these
symptoms. These symptoms are usually mild.
- Sexual Functions
It is not necessary to abstain from sexual activity, however,
a condom should be used for the first several sexual encounters
or for the first several months to avoid ejaculating a radioactive
seed into another person.
- Erectile dysfunction (ED), or difficulty
with erection during sex, may occur immediately after the implant.
This is likely due to bruising of the nerve to erection. This
may recover spontaneously. In the meantime, ED can be treated
very successfully with Viagra, Cialis, or Levitra. Some patients
report a mixture of pleasure and pain during orgasm. Usually
the discomfort resolves by three to four months. The semen is almost
always discolored (dark) for several months due to the presence
of old blood. The ejaculatory ducts may become blocked, and semen
production by the prostate may be impaired, resulting in a marked
diminution in the volume of ejaculatory fluid at the time of
orgasm.
- Miscellaneous
symptoms
Patients usually experience some fatigue. It usually resolves
within three to four months. Blood counts are not affected by
this treatment. There will be no hair loss.
Complications of Seed Implant Therapy
Complications refer
to long-term or permanent problems. If a complication occurs, that
does not mean that there was an error in the treatment. Whenever
cancer cells are being "killed," normal healthy cells can be
temporarily or permanently damaged. The same holds true for hormone
therapy, external beam radiation, and radical prostatectomy.
- Urinary Incontinence
After the urinary urgency has resolved, urinary incontinence,
the involuntary loss of urine, is infrequently seen (< 1% of patients).
However, patients who have had a prior transurethral resection
of the prostate (TURP), sometimes called a “roto-rooter job,” have
an increased risk of incontinence of about 5 percent. Patients
with large TURP defects are not implant candidates. If incontinence
develops following a seed implant, it is usually mild, requiring
no more than one to twon pads per day.
- Urinary Structure
About 5 percent of patients develop a urinary stricture or bladder
neck fibrosis. This means that scar tissue has formed, and has
caused narrowing of the urethra, or scarring of that portion of
the bladder, which is near the prostate. This results in a weak
urinary stream, frequent bathroom visits at night or inability
to urinate. Initially the treatment of choice is alpha-blockers.
If the urinary flow is completely blocked, a temporary catheter
is placed. Surgery is not often required, and should be considered
a treatment of last resort. When surgery is contemplated it is
best to wait one year. The procedures most commonly used are: 1)
a “mini-TURP”;
2) a trans-urethralincision of the prostate (TUIP); 3) a bladder
neck incision; or 4) a trans-urethralneedle ablation (TUNA). Before
any surgery is contemplated, the patient’s urologist should consult
with his radiation oncologist. Experience has shown that in many
cases the blockage will resolve by itself without surgery. The
primary risk of these surgical procedures is permanent and sometimes
severe urinary incontinence.
- Rectal Injury
The most common rectal injury is chronic rectal bleeding. Rectal
bleeding may result from pre-existing hemorrhoids, a rectal cancer,
or from fragile blood vessels that form on the rectal wall as
a result of the radiation. These fragile blood vessels are
not dangerous and can usually be treated successfully with
suppositories. If rectal bleeding occurs, please notify your radiation oncologist.
You may need to see a gastroenterologist (a GI doctor).
- IT
IS OF THE UTMOST IMPORTANCE THAT YOU INFORM YOUR GI DOCTOR THAT
YOU HAVE HAD A PROSTATE SEED IMPLANT. IT IS NOT SAFE TO HAVE
HEMORRHOID SURGERY OR CAUTERY ON YOUR RECTUM. THERE HAVE BEEN CASES
WHERE SUCH PROCEDURES HAVE RESULTED IN SEVERE RECTAL INJURIES REQUIRING
A COLOSTOMY. WE ADVISE YOU TO SHOW THIS PAGE TO ANY PHYSICIANS
TREATING YOU FOR RECTAL BLEEDING.
- There
are new laser therapies, which are very superficial and are more
likely to be safe, but this should only be used in cases of severe
rectal bleeding that cannot be controlled by more conservative
means.
- Rectal
ulcers are very uncommon. The first sign of an ulcer may be moderate
to severe rectal pain, which is usually associated with bleeding.
However, these symptoms can also occur with hemorrhoids. RECTAL
ULCERS MUST NOT BE CAUTERIZED, LASERED, OR OPERATED ON.
- THE MOST SEVERE
RECTAL INJURY IS A FISTULA. Fortunately, fistula are very uncommon. A
rectal fistula is a hole that develops between the rectum, and
the bladder or urethra. The first signs are pain associated with
the leakage of urine through the rectum. Usually a colostomy must be
done. FOLLOWING SEED IMPLANTS, RECTAL FISTULAS CAN BE CAUSED BY
CAUTERY FOR RECTAL BLEEDING, OR HEMORRHOID SURGERY. THESE MUST
BE AVOIDED.
- ERECTILE DYSFUNCTION
Erectile dysfunction (ED) is the most common complication following
all treatments of prostate cancer. The good news is that most
cases of ED following seed implant therapy can be successfully
treated with medication (Viagra, Levitra, or Cialis). If a patient has
good erections prior to treatment, the probability that he will
maintain an erection satisfactory for sexual intercourse after
treatment is about 80 percent; however, the majority of patients
will use one of these medications at least some of the time.
If the erection is already impaired prior to the seed implant,
these drugs are less likely to work. If they are unsuccessful, other
treatments such as penile injections may prove effective.
- For
several months following the implant, the ejaculate may be discolored.
Usually the color is very dark as the result of old blood. Eventually,
most patients report that the ejaculate dries out, and that very
little semen is ejaculated. Fortunately, the quality of the orgasm
is usually not affected.
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