Radiation
Oncology Department -
Radioactive Seed Implant FAQ
.
What kind of patient is best
suited for seed implant therapy? This procedure is an alternative for men who have early-stage prostate cancer. Seed implant alone is used for patients who have a low risk of disease outside the gland. External beam radiation plus seed implantation is used in situations in which there is a greater risk of disease outside the prostate. Seed
implantation is also an attractive option for men whose poor health precludes radical prostatectomy.
.
What parameters--PSA, Gleason score or other--should a man have in order to be a candidate for seed
implantation? Most men will be a candidate for seed implantation. Some will have a large gland, unusual anatomy, or TURP defect which technically prevents a good implant. In general, patients with PSA less than 10 and Gleason score of six or less are good candidates for implant.
.
What PSA level is hoped for over the long term? What is a good level of PSA after seeding? Most of the literature supports the observation that patients achieving a PSA level less than 1.0 have a better prognosis. Many patients have stable PSA readings above 1.0. It is speculated the PSA rises to this level because of regrowth of their normal prostate cells, similar to the way BPH can increase PSA. A stable PSA is probably more important.
.
What are the advantages of seed implantation compared to other
treatment options? Seed implantation is associated with lower rates of impotence and incontinence compared to traditional treatments, such as radical prostatectomy and external beam radiation.
For most patients, seed implantation is a one-time, low-impact procedure. Patients can return to normal activity, including work, within one to three days, with little or no pain. Radical prostatectomy patients remain in the hospital for 3-5 days and require weeks of recovery at home. External beam radiation patients must visit a radiation treatment center daily (Monday through Friday) over a seven to eight week
period. Seed implantation can usually be performed on an outpatient basis, which translates into cost savings.
.
Does radiation from seed implants
pose any danger to organs or tissue
surrounding the prostate? Because seeds are implanted with pinpoint accuracy into the prostate, they pose little risk to surrounding organs or tissue, therefore having low complication rates. The radioactive isotopes used in this procedure, Iodine, decay over a period of a few months.
.
Am I radioactive after
the seed implantation? No. Although the seeds are radioactive, you are not. The radioactivity is so low and the placement so precise, virtually all radioactivity is absorbed into the prostate. Special precautions should be taken when you are in contact with small children and pregnant women in the first two months after treatment. The risk to pets from sitting on your lap is extremely low.
.
Does the radiation from seed implants
pose any danger to my sexual partner? No, the seeds are of low energy and pose little risk to the partner. You may resume sexual activity shortly after the procedure. Occasionally seeds are placed into the seminal vesicles and thus it is possible, but extremely unlikely, the seeds might be mixed with your ejaculation fluid. The initial climaxes may be slightly painful or the semen may contain blood, both of which may be undesirable, so use a condom. The semen is not radioactive.
.
Is there any nutritional changes I can
make in my diet to improve the health
of my prostate? Many patients tell us nutritional supplements or herbal remedies improve their urinary function or reduce their PSA levels. Unfortunately, there are no good studies to support one regimen or another. Most do no harm and therefore we do not object their use.
.
What are the names for this procedure?
How does radiation from seed implantation affect cancer cells? How will the radiation from seed implantation affect healthy cells in the prostate?
Radiation kills cells primarily by affecting a critical target in the cell. This critical target is the DNA or RNA, elements of the cancer cell which are important for growth. Cancer cells don't die immediately after radiation. Instead, when the cell tries to divide into two cells, the effect of radiation on the DNA/RNA prevents the cancer cell from dividing properly and the cell dies. Since prostate cancer cells often divide slowly, the cancer cell may not die for months after the implant. This is why it sometimes takes a long time for the PSA to drop to low levels. Since cancer cells are most sensitive to radiation at the time of division, it is good to have some radiation present when this occurs.
How will the radiation from seed implantation affect healthy cells
in the prostate?
All cells are sensitive to radiation. Normal prostate cells die as a result of the implant radiation. Some remain however, which explains why PSA is still present years later. The result of healthy cells dying is that the prostate function of producing fluid for ejaculation may be substantially reduced. The presence or absence of an ejaculate does not reflect whether or not the cancer is cured.
Will healthy cells regrow after
the radiation is complete?
We believe there is some regrowth of normal cells, but for the most part regrowth is probably very slow. This regrowth of normal prostate cells is believed to be responsible for PSA values after treatment originally dropping then beginning to increase in some
patients.
What dose of radiation will the
seed give during its lifetime?
It depends whether the seed is used as an implant alone or in conjunction with external beam radiation.
Implant alone Iodine 160 Gray (=16,000 cGy or
rads); EBRT and Implant Iodine 120 Gray (=12.000 cGy or rads)
4500 cGy.
Note that a new description for Iodine doses (TG 43) is being adopted by many centers. This is not a change in the energy given or seed strength used, but a means for physicists and physicians to describe more accurately what dose is given. For example instead of 160 Gy the new prescription will be 144 Gy. Patients should not worry they are getting less dosage by this new method. It is the same dose used with the older system.
Please explain seed "half life." How long will the seeds be radioactive after implantation?
"Half life" describes the time in which an isotope loses half its strength. For example, Iodine, which has a half life of 60 days, will be half its strength at 60 days. Sixty days later it will be half of this strength. It takes about six months for Iodine to be about 10% of its original strength and a year to lose all strength.
Why do some patients receive external beam radiation therapy (EBRT) in addition to seed implantation?
Seed implantation alone (like surgery) presumes the cancer is only in the prostate. For many patients this is highly likely. In general, patients with PSA less than 10 and Gleason score of six or less are good candidates for implant alone. However some patients have higher risk of disease outside the gland and therefore would benefit from external beam radiation. The physicians will decide based on PSA, grade and stage. Patients with a high risk of disease outside the gland generally receive a short course of external beam radiation (5 weeks) following seed implantation.
What side effects might be
expected from either EBRT?
Radiation to the prostate region can affect the bladder, urethra, and rectum. Typical symptoms during treatment are: increased urinary frequency, urgency, slower stream, irritation during urination, rectal tenderness, slight diarrhea or more frequent bowel movements, and tiredness. These symptoms usually resolve shortly after the treatment is
completed.
Can seed implantation cause long
or short-term incontinence?
The risk of long term incontinence after either seed implant alone or in combination with external beam radiation in the typical (non TURP) patient is extremely low, less than one percent. Short term, some patients experience significant urgency and may have difficulty reaching the restroom without some slight dribbling. This resolves as the seeds lose their energy.
Please explain why nighttime is worse than daytime for urine retention and difficulties in urination?
For many men nighttime urination is a different experience than during daytime. Often the stream is slower or difficult to initiate. This phenomenon can be worse after seed implantation or external beam radiation. We believe this results because there is slightly greater swelling of the prostate at night. Alpha blockers (Cardura or Hytrin) are often
prescribed to help minimize this symptom and it generally goes away as the seeds lose their
energy.
Do you recommend any strategies for alleviating nighttime urinary problems?
Alpha blockers (Cardura and Hytrin) can often help. Finding the correct dose can be a challenge sometimes. Other techniques to improve flow are: walking around, getting into a warm shower or bathtub and urinating, or taking Aleve or other anti-inflammatory drug.
Should I continue to drink fluids throughout the day and evening or should I reduce or stop fluid intake in the evening?
The advantage of taking fluids (particularly water) after seed implantation is it dilutes and neutralizes urine pH. Concentrated or acidic urine can be irritating. The disadvantage of taking larger amounts of fluid than normal is more urination, possibly increased episodes of urgency and having to get up more times at night. In general we don't feel more fluid is better.
The type of fluid you drink may be more important. Fluids that cause the urine to be acidic such as fruit juices and coffee should be kept to a minimum. Everyone is different though and often even these fluids do not cause any problems. You need to test these fluids for yourself. Use common sense, and stop any fluid if it makes it worse.
What are the effects of seed implantation on short and long term potency?
The effect of the implant on potency can be immediate or delayed. Studies so far indicate overall, approximately 25 percent of men who are fully potent (able to achieve an erection) prior to implantation, will become impotent after the procedure. Another 25 percent will experience some decrease in their potency but still have intercourse. At present we have no way of predicting who may be affected and
when.
If I am fully potent prior to complete hormonal blockade (CHB) and or seeding, what is the likelihood of
regaining/ retaining potency in the short and long term after seed implantation?
In a patient research questionnaire sent out several years ago 20-25 percent of men fully potent prior to implantation became impotent (unable to achieve erection). Another 20-25 percent experienced a decrease in the firmness or durability but were still able to penetrate.
What part does age play in loss of potency or incontinence after seed implantation?
We have noticed men over 70 have a slightly greater chance of impotency, and may be part of the natural aging process. We have not found age is related to the risk of
incontinence.
Procedure (Before)
A volume study is the first step of the mapping procedure. This is an ultrasound procedure in which images of the prostate are taken at 5 mm increments. These images are then reassembled on the computer to make a three dimensional model. Using this model, we determine the exact placement of each seed. After a careful review by each member of the team (physician, physicist, dosimetrist, and nurse), a map of the gland is created which describes the correct coordinates for needle and seed placement. This map is taken into the operating room and followed closely. Additional seeds are available in order to make adjustments at the time of
surgery.
You often ask for a CT scan for pubic arch evaluation at the time of consultation. Why?
One important determination after the volume study is deciding whether seed implantation can be technically performed by evaluating the size of the prostate in relation to the position and shape of the pubic arch. Many patients have small enough glands and this test does not need to be done. The implant requires placing needles into the prostate. If the pubic bone, which is shaped like an upside down V or arch, is too narrow, it can be difficult or impossible to place the needles accurately. Determining whether the pubic arch will prevent a good implant is valuable. For those with larger glands and arch interference, shrinking the gland with hormonal therapy can often make the patient an implant candidate.
Please describe the type of anesthesia.
The anesthesia is dependent upon your medical status and personal preference. You will meet with your anesthesiologist the day of the implant. He will interview you, explain, and discuss with you possible options. However, these procedures are usually done with either a spinal or general anesthesia.
What medications do you prescribe
before and after the procedure?
Typically we prescribe an alpha-blocker (Cardura or Hytrin) prior to the procedure. These medications relax the internal muscle of the prostate, allowing for improved urination. Because it can take a few days to reach a proper dose, we like to start it several days prior to the procedure.
After the procedure patients typically continue the Cardura for several weeks, longer if necessary. In addition patients are given an antibiotic and an anti-inflammatory drug such as Aleve. Aleve helps reduce swelling of the prostate, which is normal, as well as often improving urine flow.
Under what circumstances would you recommend combined hormonal blockade (CHB) for seed implant candidates prior to the procedure?
The use of combined or sometimes called complete hormonal blockade (CHB) in treatment is increasing. The advantage, for patients with large glands, is it can reduce the size of the prostate, allowing for a technically ideal implant. Several EBRT studies also demonstrate an advantage to using CHB prior to and during treatment. This fact, plus the relatively few side effects of CHB prompts regimens using CHB in combination with the implant
regimens.
What effect does CHB have on the cancer and how does it's inclusion support the seed implant procedure?
CHB results in significant cancer cell death, but unfortunately does not kill all cancer cells. It also reduces the number of normal cells. Radiation is more effective when there are fewer number of cells it needs to kill. Therefore, CHB is attractive as an additional treatment, especially in those situations in which there is a bulky cancer or a high chance of disease outside the
gland.
Do you recommend Kegel exercises
before or after seed implant?
Kegel exercises are exercises of the external urinary sphincter, the muscle which allows one to control the urge to urinate. This muscle can be impaired or weakened naturally or as a result of the implantation. Kegel exercises can increase the strength of this muscle, allowing for more control of urgency often associated with the implant. It doesn't hurt to do them and may help.
What kind of physician performs the radioactive seed implantation procedure and in what setting?
Radioactive seed implantation is performed in a hospital setting by a team of physicians consisting of a urologist and radiation oncologist.
What soreness, discomfort or pain should I anticipate after the implant? How long will it last? What medications are available to deal with discomfort or pain?
After the implant, there typically is some soreness underneath the scrotum. Occasionally patients describe feeling like they are "sitting on a golf ball." This is due to slight swelling and bleeding associated with the surgery and gradually resolves. Most patients require only mild medication like Tylenol extra strength. Narcotic pain medications are rarely required.
Is there any chance of infection?
If so what should I do about it?
With all surgical procedures there is a chance of infection. Therefore, you will take an antibiotic for about a week after the implant. Occasionally patients develop urinary tract infections or prostatitis months or years after the implant and require antibiotic therapy.
How long will it take for the effects of Lupron and Casodex to wear off?
Patients respond differently to these hormonal agents. Typically, it takes one to six months for the symptoms (hot flashes, tiredness, etc) to
wane.
Procedure (After)
How can I expect to feel the remainder
of the day after the procedure?
Like all procedures, patient response varies. The procedure causes minimal trauma to the region beneath the scrotum, but there can be tenderness and bruising. Most patients require only minimal pain medications such as Tylenol extra strength. After the procedure most patients are somewhat tired and want to relax. You can do normal activities (walk around, dinner, etc.) if you feel up to
it.
Why will I have a CT scan and
Chest x-ray soon after the procedure?
The CT scan confirms the placement of the seeds and allows the implant team to perform a dose determination called dosimetry. The post implant dosimetry acts as a permanent record of the implant and gives the implant team another means of evaluating the quality of the implant.
Also on rare occasion, a "free" seed (a seed placed in the needle individually) is inadvertently implanted in the middle of one of the large veins around the prostate. This seed can travel in the veins, eventually reaching the lungs. Seeds in the lung have caused no adverse symptoms or harm to any patient. The chest x-ray is performed to determine if a seed is in the lung. If this happens, we want you to know right away, as the seeds will continue to show up on any future chest or pelvic
x-rays..
What is the likelihood of blood in the urine and passing blood clots after the procedure?
It is very likely blood and/or clots will be noticed in urine immediately after the procedure. This usually resolves within twenty four hours, but occasionally lasts longer or occurs spontaneously some time after the implant. If blood in the urine persists, an evaluation is appropriate, and you should call your urologist.
How long is it possible to pass
seeds through urination or sex?
If seeds are passed, it will happen in the majority of circumstances during the first few urinations or climaxes. It is extremely rare for a seed to be lost in this way beyond this time.
Are there any other side effects from radioactive seed implantation? What ongoing pain/side effects might occur
days after the procedure?
After radioactive seed implant, less than one percent of patients, who had no prior surgery ( i.e. TURP), will become incontinent. About 20-25 percent will become impotent and another 25 percent partially impotent.
As a result of the implant procedure, some men experience mild discomfort in the groin area for two to three days, which is managed very effectively with mild analgesics. Some blood may be seen in the urine and sperm for a few days after the procedure. This is normal and stops after two to three days. The scrotal and perineal area can also become swollen or bruised.
The effects of the radiation seeds usually begin one to two weeks after seed implantation. The main symptoms are urinary difficulties such as frequency, urgency, weak stream or slight pain. These can last for two to six months and can usually be controlled with medications. Occasionally a temporary catheter is necessary.
When should I expect to resume normal activities? How soon after seed implant should I be able to begin strenuous exercise? How long should I wait before going back to my exercise routine?
The insertion of the needles causes some trauma to the vessels surrounding the prostate. Immediately after the implant, any exercise or activity putting pressure on the prostate should be avoided. We recommend not lifting heavy objects or vigorously exercising for at least three to four days after the implant. Very vigorous exercise after this period may cause some minor bleeding in the bladder. This is not harmful, but we ask you to limit your exercise until the bleeding stops.
Activities such as bike riding, horseback riding, motorcycle riding in which there is pressure on the prostate should be avoided for at least six months. The pressure and repetitious jarring of the prostate with these activities can cause some swelling and impair urination.
How long should I wait before
sexual intercourse?
Patients can engage in sexual activity any time after the implant using a condom with the initial encounter. This is recommended should a seed fall into the semen. The semen is not radioactive and if there is some blood in the semen this represents no danger to your partner.
To what extent and for how long should I limit my exposure to pregnant women and young children? What is defined as young? How long should I wait before I can come into contact with them?
There is a small amount of radiation from the isotope Iodine. While there are no reports of harm to someone near an implant patient, we feel it is prudent to observe some precautions and avoid exposure to pregnant women and children under 12. The seeds lose their energy quite quickly and waiting two months before close, prolonged contact is prudent. Patients can have normal contact time such as brief hugging, sitting at the dinner table, sitting on airplanes, etc. before the two months. Simply keep a modest distance such as 4-6 feet if the contact is going to be prolonged (more than several hours).
.
|
