About Brachytherapy Treatment for Prostate Cancer
Q. Does it matter who does my implant?
A. Prostate brachytherapy (PB) should be performed by a team comprised of a radiation oncologist, urologist, and physicist. Because PB is a complex procedure (unfortunately a fact that is not appreciated by many of those new to the procedure), it is one that cannot be done well if taken casually or done infrequently. Ideally the team should have performed many procedures, perform them weekly, and know how to describe the quality of their implants in terms of dose coverage. A definite learning curve is appreciated for this technique. The number of physicians performing PB has markedly increased recently and as a result, there are many physicians in their early years of experience who are still on this learning curve.
Q. How do I know if I get a good quality prostate implant?
A. The best way to get the best quality is to carefully choose your brachytherapy team as described above. It is standard of care to perform post-operative radiology studies within the first month following prostate brachytherapy (PB) – to calculate actual doses delivered to the prostate, urethra, and rectum. For a variety of reasons, these doses often differ from the doses intended or “prescribed.” This study provides very important prognostic information to the physicians and patient regarding implant quality. This subject is a major area of research interest for our group and one reason why Texas Cancer Clinic’s practitioners are considered world experts in the field of PB.
Q. My doctor said that if the cancer returns after my seed implant, there is nothing more that can be done. Is that true?
A. No. However, it can be confusing to try to decide on treatment based on a lot of “what if’s.” Treatment decisions should be based on 1) cancer control rates and 2) quality of life issues. It is important to realize that only about 10% of properly selected patients with good quality implants will fail treatment. Of those who do, interventions can range from observation to external beam radiation to re-implant to hormone therapy to radical prostatectomy. Because many urologists have not ever performed “salvage” prostatectomy they will tell patients it is not possible. However, there are expert surgeons who have successfully performed this procedure. Re-treatment is always more risky than the original treatment. Patients who fail radical prostatectomy, for example, face the same concerns of increased risk and complication if subsequently treated with radiation therapy.
Q. How much will a prostate seed implant disrupt my lifestyle?
A. Most patients feel surprisingly well on the day following implantation. Some have gone as far as playing a round of golf (we don’t recommend that). Certainly by the next week, nearly all are able to return to their normal routine including work and other activities. Bladder irritation will cause urinary frequency and some sense of urgency by the third or fourth week following the procedure, but this rarely significantly affects lifestyle. We recommend abstaining from sexual intercourse for at least two weeks, and to refrain from bicycle riding for 2-4 weeks, but otherwise there are no limitations.
Q. I have heard that prostate implants were tried many years ago and didn’t work. Why should they work now?
A. There are two reasons. 1) Improvements in our ability to properly select patients, partly based on our experience in those early years, as well as more recent data. 2) Improvements in implant quality as a result of advances in ultrasound imaging, computerized dosimetry, and tools and devices used in the procedure. The early attempts at prostate brachytherapy (PB) did not use imaging or computers (they were performed by “feel” and eye). In retrospect, it appears that although the results in the early experience with PB were generally unsatisfactory, among those few patients properly selected by today’s standards and fortunate enough to receive decent implants, results were quite favorable. Unfortunately, many physicians (including urologists) especially those trained in the prior generation, remain biased against PB because of their experience with these primitive techniques. Many can’t appreciate the vast improvements in the techniques of today.
Q. What is the difference in the two types of seeds?
A. The radioisotopes used in prostate brachytherapy (PB) today are I-125 and Pd-103. I-125 has a half-life (time for the dose rate to decay to one-half) of about 60 days while Pd-103 has a half-life of 17 days. While it was once thought that one was better than the other depending on Gleason Grade, more recent studies and experience indicate no detectable difference in outcome between the two isotopes. It appears that the quality of the implant, i.e. how well the prescribed dose covers the prostate without large areas of “hot spots,” is far more important than which seed is used. Because of its initial higher dose rate and shorter half-life, Pd-103 may give slightly more intense side effects but for a shorter period of time relative to I-125. For these reasons, many believe that if an implant is to be given initially, in combination with external beam, Pd-103 is better suited for this sequencing, primarily to avoid simultaneous radiation with the external beam treatment (EBT). If implant is to follow EBT, the choice of isotope may be less important. At this time Pd-103 is more expensive than I-125, but with new suppliers of both isotopes on the market, it is hoped that the cost of both will soon decrease.
Q. How do I know if the implant works?
A. The primary methods of follow-up after either External Beam Treatment (EBT) or Prostate Brachytherapy (PB) or a combination of these are Digital Rectal Exam (DRE), Prostate-Specific Antigen (PSA) level, and prostate biopsy. DRE is notoriously misleading, especially since often it is normal before treatment. Measuring the PSA level is the most useful method of follow-up. We do not recommend checking this serum blood test for several months after implant since it usually drops very slowly and may even temporarily increase in the short term due to trauma to the gland from the procedure. It is not unusual for the PSA to continue to gradually drop over the course of 18-36 months or even longer (42 months in one report). Prostate biopsy has been found to add relatively little information beyond the PSA, and for this reason we do not routinely recommend it except for research purposes or to confirm the suspicion of local recurrence. Although it appears that patients with PSA values which drop below 1.0 ng/ml do very well, probably the lower it drops, the better.
Q. I’m 82 and very healthy. Am I too old for brachytherapy?
A. Generally, for men of average health, potentially curative treatment is not offered beyond the mid-seventies. However, some older, very healthy men are candidates for treatment because they have aggressive-type cancers and a rising PSA. Since the rigors of implantation are markedly less than surgery, such men would be better treated with brachytherapy than surgery. The alternative of prolonged androgen blockade has significant side effects, so treatment of the local cancer with a local therapy may be better. Successful treatment with brachytherapy in such cases may prevent the need for hormonal therapy altogether.
Q. I’m 49, with a Gleason Score 6 cancer in 1 of 6 biopsies and a PSA of 5.2. My urologist says that because of my age, the “Gold Standard” of surgery is the only option I should consider. Is this true?
A. No. First of all, there is no proof that surgery is better than well-performed brachytherapy. Secondly, surgery is not a “Gold Standard.” Urologists have the longest experience with surgery, and are biased toward it because that is what they know best. Many are against both external beam and brachytherapy. There have been no clinical studies comparing surgery and either form of radiation in similar patients randomized to one or the other. The 14-year follow-up data from Seattle shows a PSA control rate (<0.5) og 87% for early stage patients. The only 15-year PSA control data for surgery is a single study from the Mayo Clinic showing success at that point in only 44% of patients.
Q. Some people doing brachytherapy use hormonal therapy (androgen blockade) in all patients. Is this necessary, since I would really prefer to avoid it?
A. In recent years, the demand for seeds so outstripped the supply that hormonal therapy was used during the 2-3 months required to process the order for seeds. Patients were often told there was a need to shrink the prostate. Now, seed manufacturers have markedly increased production capacity, and there is not a large delay in obtaining seeds. The only patients who really do need to receive androgen blockade before implantation are those who truly require prostate shrinkage because the volume is over 60 cc, and those with high risk disease who are also undergoing combined external radiotherapy. In our experience, pre-implant androgen blockade is necessary in only 30-40% of patients
For further information on about Brachytherapy Treatment for Prostate Cancer Please click here.