Frequently Asked Questions
The following are some of the most frequently asked questions (FAQ) regarding prostate cancer, treatments and the Prostate Cancer Center of Seattle.
In order to be a candidate for seed implantation what parameters, PSA, Gleason score or other, should a man have?
In general, patients with PSA less than 10 and Gleason score of six or less are good candidates for implant alone. Most men will be candidates for seed implantation (S.I.). S.I. is performed either alone or in combination with external beam radiation. A risk group (low intermediate and high) will be determined for your cancer at the time of consultation. These risk group classifications will help us decide the appropriate treatment approaches that will suit your condition. See the explanation of risk groups. Most low and intermediate patients are candidates for seeds alone however higher risk patients may require a combination of IMRT and seeds or hormonal therapy, IMRT and seeds for the highest risk situations. See the Prostate Cancer Results Study Group ( under Prostate cancer heading) for more information. Some men will have a large gland, unusual anatomy or TURP defect, which technically prevents a good implant , but this occurs rarely.
What factors do you take into consideration when picking Palladium 103 or Iodine 125 for the implant?
Gleason grade has been, in the past, the primary determinant for picking an isotope. Early open (laparotomy) implant experience with I-125 with moderate grades (2-6) was quite favorable but not so favorable with high-grade tumors (Gleason 8-10). We therefore initially elected to treat patients with low to moderate grades (2-6) with Iodine 125 and higher grades (7-10) with Palladium 103. To date, this has worked out well. For Gleason scores 5-7, either isotope is probably effective. However the studies that have evaluated whether one isotope is superior to another have demonstrated no difference.
Please describe the volume study and the mapping of the prostate.
The volume study is an ultrasound study done prior to the implant which allows us to evaluate the size ad shape of the gland . Similar to t he ultrasound biopsy but without the biopsy, patients are placed on the exam table identical to the time of the procedure. Pictures are taken of the prostate form the base of the gland to the bottom ( apex) whihc are then used to design a custom placement of the seeds.
How Long Does the procedure take?
Typically, the procedure takes about an hour and is done under spinal or light general anesthesia. Either approach is acceptable. Note that with a spinal anesthetic, the type and amount of anesthetic agent determines how long it takes for the anesthesia to wear off but usually with the short acting agents we use, either general or spinal, the anesthesia wears off within thirty minutes of the procedure.
What can I expect to feel like the immediately after the procedure?
As with all procedures, patient response is varied. The procedure causes minimal trauma to the region beneath the scrotum, but there can be some tenderness and bruising. Most patients require only minimal pain medications such as Extra Strength Tylenol. After the procedure, you may be somewhat tired and want to relax. You can engage in normal activities (walk around, have dinner, etc.) if you feel up to it.
Why will I have a pelvic CT scan soon after the procedure?
The CT scan is done to confirm the placement of the seeds. The CT allows our implant team to do a dose determination called dosimetry. The post-implant dosimetry acts as a permanent record of the implant. It also gives us another means of evaluating the quality of the implant. On very rare occasions, additional therapy may be suggested.
Will you explain the differences between palladium, iodine seeds and Cesium seeds?
Iodine (I-125), palladium (Pd 103) and Cesium CS 131 seeds are nearly identical in their appearance. All are titanium shells 0.45 cm long (about the size of a grain of rice) and have either I-125 or Pd 103 or Cesium 131 isotope within them. All are implanted in the same way. All emit low-energy radiation. The primary difference between these isotopes is the rate at which they give off their energy. Pd 103 gives up 90% of its energy within two months, while it takes approximately six months for I-125 to release 90% of its energy and Cs 131 36 days. There are advantages to using one isotope over another isotope, which is described below in a related question about seed selection. There is no proof that one seed is better or stronger than another. While the dose prescriptions and seed strengths are slightly different, the doses and seed strengths, in fact, are prescribed to produce the same biologic effect.
What dose of radiation will each kind of seed deliver to the prostate during its lifetime?
It depends on whether the seed is used as implant alone or in conjunction with external beam.
What is a seed’s “half life”? How long will each kind of seed be radioactive after implantation?
Half-life describes the time in which the isotope (I-125, Pd 103 or Cs131) loses half of its strength. For example, iodine, which has a half-life of 60 days, will be half of its strength at 60 days. 60 days later it will be half of this strength. It takes about six months for iodine to be at about 10% of its original strength and a year to lose all of it.
Palladium has a half-life of 17 days. Within two months it has given up 90% of its energy and has lost almost all of it by six months. Again, there are advantages to both isotopes. Palladium gives up its energy quicker but this does not mean that it is necessarily better or stronger.
Cesium 131 has a half life of 9 days. Within a month it has given up 90% of its energy.
How does radiation from seed implantation kill cancer cells? Are there forms of prostate cancer cells that will not be killed by seed implantation radiation? How will the radiation from seed implantation affect the healthy cells in my prostate?
Radiation kills cells primarily by affecting a critical target in the cell. This critical target is believed to be 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 the 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 many months after the implant. There are also normal prostate cells which die very slowly as a result of the same process. This is why it sometimes takes a long time for the PSA to drop to low levels. Since the cancer cells are most sensitive to radiation at the time of division, we like to have some radiation present when this occurs. This is the rationale that, for slower growing cancers, Iodine 125 is used. For faster growing (higher-grade) cancers, the division is quicker and therefore it is argued to use Palladium 103, which gives up its energy more quickly.
All cells are sensitive to radiation. Normal prostate cells die as result of the implant radiation. Some normal cells remain or die VERY slowly, which explains why some PSA may still present years later or continue to decline for years. When the cells of the seminal vesicles, (which are adjacent to the prostate) die, the prostate’s ability to produce prostatic fluid for ejaculation may be substantially reduced. The presence or absence of an ejaculate, however, does not reflect whether the cancer is cured or not.
Will healthy cells re-grow after the radiation is complete?
There can be some regrowth of normal cells, but for the most part re-growth is very slow or absent. This regrowth of normal prostate cells is believed to be responsible for the presence of PSA in some patients after treatment.
Will my BPH (benign prostatic hypertrophy) go away or return later after an implant?
No investigator has looked at this issue carefully. However despite that , the gland will shrink after seed implantation, often patients have urinary function similar to that prior to the implant. In other words, at this point seed implantation does shrink the gland substantially but may not change the symptoms of BPH.
What are the chances I will be affected by prostatitis after seeding?
All patients have some inflammation of the prostate (prostatitis) after seeding which typically resolves as the seeds lose their energy. The presence of prostatitis prior to seeding is always a concern of patients because they believe their prostatitis may be exacerbated by the radiation. Surprisingly, this has not occurred in the patients we have treated. This is not to say that prostatitis symptoms will completely go away after implantation but that the implants did not seem to have significantly worsened them.
What effect does a TURP have on treatment?
A TURP is performed to relieve urinary obstructive symptoms. In some patients, the presence of a previous TURP prevents a technically good implant. In the past, our patients with a prior TURP had approximately a 30 percent increased risk of urinary incontinence at six years. The majority of this incontinence was minor, requiring a simple pad. Over the past several years urologists typically remove less tissue and we have modified the pattern of seed placement in these TURP patients which has decreased these problems substantially. We advise patients with a prior TURP that their risk of incontinence is likely slightly higher. If they are not candidates for seed implantation, there are, of course, often very good alternative treatments (radical prostatectomy or external beam radiation).
TURP after an implant also imparts a risk of incontinence. Therefore, a TURP after an implant is not generally recommended. We generally recommend a TUIP (transurethral incision of the prostate) which is simply an incision to open up the gap causing the blockage. This is usually easier and can be repeated. When a TURP is necessary after implant, it should be performed by someone who understands the problems associated with it in seed implant patients.
What follow up will there be after seed implantation?
The first visit is at 6-8 weeks and thereafter every three months for two years. After two years, visits are recommended every six months. After five years, a PSA is scheduled every six months and a physical exam at least once a year. Alternating these visits between the radiation oncologist and urologist insures complete care. If you have a good internist or family practitioner, we encourage his/her participation as well. Most important is to have concerned, knowledgeable physicians following your care course.
What are the effects of seed implantation on short and long term potency?
Patient ability after implantation is affected by ability prior to treatment. Patients with normal erectile function have approximately 10% likelihood of losing the ability to penetrate at 2 years. Approximately 50% of patients will require an agent like Viagra or Cialis to improve their performance. Approximately 75-80% of these patients will achieve improvement in their erections. The newer technology (Thin Strands, Source Link) as well as planning techniques and rehabilitative regimens are expected to improve the results. Dr Grimm will discuss your specific situation with you. At present, there is no way of predicting who will be affected and when.
Can seed implantation cause long or short-term incontinence?
In our experience, 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 1%. 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 daytime, with often a slower stream or difficulty initiating a stream. This phenomenon can be worsened after seed implantation or external beam radiation. The reason for this is unclear. It may be worse at night because there is slightly greater swelling of the prostate at night. Alpha blockers (Flomax, Doxazosin ( Cardura) or Uroxatrol) are prescribed to help minimize this symptom. Often, walking around will alleviate this problem. Generally, this worsening of the urinary stream at night goes away as the seeds lose their energy.
I have heard that your physicians left their previous center The Seattle Prostate Institute. Is there a difference in experience between the two centers?
Drs. Grimm and Sylvester left the Seattle Prostate Institute in July, 2009 to start the Prostate Cancer Center of Seattle. The nurses, dosimetrist and administrative staff also left SPI to join the Prostate Cancer Center of Seattle team. Dr John Sylvester has joined a large Urology /Radiation group in Florida .