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Old 05-21-2010, 09:13 PM   #1
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Post Choosing a therapy - lessons from the Prostate Cancer Results Study Group

Today I became aware of a much needed new resource, an informal publication of results from the Prostate Cancer Results Study Group (PCRSG). This is a set of summarized advice divided by risk category, meaning the risk that the prostate cancer is beyond the prostate capsule. It was compiled by a large group of distinguished physicians representing various treatment approaches who reviewed published studies to see if they could develop conclusions as to which therapy was best (they could not), or at least provide insight into which seemed to work well in various circumstances and which did not (they succeeded).

I posted fairly briefly about this on 9/17/2009 6:14 PM in a report on my experience at last year's National Conference on Prostate Cancer. That post included a long paragraph on the talk by Dr. John Blasko, one of the key pioneers of brachytherapy in the US. He described the work and results of the PCRSG and presented 41 slides with great graphics showing how the therapies compared. I was highly impressed with his presentation.

I have a DVD of the talk and have made copies of the slides for my own reference, but I've been waiting in hopes that the research would be formally published in a peer reviewed journal. That has not happened yet, but the PCRSG's preliminary product, including excellent graphics of results, has been published informally by the Prostate Cancer Treatment Center, the institution in the Seattle area closely associated with renowned brachytherapy experts Dr. Peter Grimm, DO, and Dr. Sylvester. (Dr. Blasko has now retired from clinical work but remains quite active in education.) The Center has made the PCRSG publication available in the set of its papers on "Prostate Cancer".

Basically, the expert panel of doctors set out to find medical research papers that described results of various kinds of treatment, but the papers had to meet some strict criteria. These included eleven main points. The first and third points combined meant that patients in the paper being reviewed must have been assigned to a standard risk group in an accepted way (my wording), and that that same risk group must be tracked in the paper after treatment. This is really critical because it prevents surgery patients from being assigned to other risk groups, particularly higher risk groups, based on pathology analysis of the prostate after the RP. Until the past half dozen years surgery for lower risk patients has looked superior because patients who turned out to be higher risk were pulled out of the study group and assigned to a higher risk group, something that can't happen with radiation and cryo, for instance. That means that we were not able to compare apples to apples in studies not meeting these criteria.

Other points included minimums: minimums for numbers of patients of 100 for low and intermediate risk, and 50 for high risk, and a minimum of five years of follow-up for all. The remaining points all were logical ways of fostering sound comparisons among therapies.

The bottom line was that brachytherapy (seeds) looks remarkably good for all risk categories, though all therapies have good records for low-risk patients. For intermediate risk patients, brachy appears to be superior to surgery, probably due to its ability to reach a few crucial millimeters beyond the prostate capsule, where 98% of any spread for low risk patients is located. However, advantages and disadvantages of each therapy for each risk level are discussed. For high risk patients, combined therapies appear to produce much better results.

The PCRSG publication shows two graphics for each risk level. (The words claim that four are shown for each, but there's a glitch with that as only two are shown, but with little loss of information. The words also say the source studies, which are identified by numbers, are cited in notes, but I did not find those notes.) The first graphic for each risk group shows the percentage of patients that are free of progressive cancer on the left, with years after treatment at the bottom, and symbols for each type of therapy per each qualifying study reviewed in the central area of the graph. However, the panel found there were relatively few studies that met all eleven qualifications, so they relaxed the criteria somewhat, accepting studies with greater than 40 months of average follow-up as well as those with five years, and, if follow-up was greater than 40 months, allowing studies of any number of patients rather than 100 as a minimum.

The publication graphics include an oval drawn around three main classes of therapy: brachytherapy and those including brachy as part of combination therapy, external beam radiation therapy ("EBRT"), and surgery.

I am interested in impressions from anyone who reads the PCRSG publication. My own reaction is that I was a bit surprised that the brachy group appears to do distinctly better than the surgery group for low-risk patients (and for all risk groups). Also, the proton beam therapy results are puzzling: only two studies make it as fully qualified studies, the follow-up is surprisingly short - only about four to four and a half years, and there is a great difference in the two results, with the superior result very near 100%, probably 98%, while the other is probably 78%, not really reassuring at just the four year point. Moreover, relaxing the criteria did not add any additional proton beam studies. I haven't found anyone who can explain why the leading proton beam centers, especially Loma Linda, are not publishing updated results in peer-reviewed journals. If anyone knows the answer, I'm sure many of us would be interested. It raises a concern that perhaps the longer term results don't stack up well against other therapy choices, though the proton centers are claiming great success.

For intermediate risk, surgery did not look impressive in most of the studies, as you would expect, while brachy or combinations with brachy continued to look quite encouraging with many studies showing progression free percentages ranging mainly from about 80% to the high 90s. Again, surprisingly, there was only one proton beam study, with discouragingly short average follow-up of about four and a half years, and success was not all that impressive at 80%.

For high risk patients, brachy alone is in only three studies (relaxed criteria) with mediocre results, but brachy with EBRT or both with hormonal therapy added look quite promising, with an abundance of studies centering with wide scattering around the 75% success line, but with a few studies above 90%. As we would expect, surgery does not look like a good bet for high risk cases. There were no proton beam studies for high risk patients.

The publication does not address side effects, but Dr. Blasko did address them, but not based on the PCRSG work. His slide #31 showed that brachy and EBRT were very close at about 12% for urinary obstruction/irritation at the 24 months point, compared to about 18% for surgery. Additional slides covered other side effects. Non-nerve sparing surgery had a level of incontinence at about 30% at the 24 month point, but that contrasted with about 21% for nerve sparing surgery; brachy was at about 15% and EBRT at about 8%. Bowel problems were best for surgery, at 5% at the 24 month point, compared to 7% for brachy and 9% for EBRT. Sexual dysfunction was the same at 24 months for surgery and EBRT at about 69%, but was only about 45% for brachy - pretty impressive at that point, but perhaps a little early to get the final picture.

Dr. Blasko, obviously a fan of brachy, summarized results of seven studies regarding brachy this way: less incontinence than surgery; less rectal morbidity than EBRT; more urinary obstructive symptoms; and better potency preservation than surgery or EBRT. His discussion of side effects did not cover proton beam therapy; that was unfortunate as proton beam may have an advantage there, as a number of board participants have stated.

The PCRSG is continuing to update its results as new studies are published, and the Prostate Cancer Treatment Center has stated they will continue to update their PCRSG publication.

This publication should go a long way in clarifying options for us.

 
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Old 06-13-2011, 07:28 AM   #2
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

There is a new way to access the latest update to the results of the Prostate Cancer Results Study Group. I just received my copy of PCRI Insights, the May 2011 edition, Vol. 14 No 2 published by the Prostate Cancer Research Institute (goes by PCRI, a non-profit organization). It has an outstanding article by Dr. Peter Grimm, DO, one of the highly respected brachytherapy doctors from Seattle, and one of the leaders behind the Prostate Cancer Results Study Group. (The PCRSG is a group of more than twenty five recognized experts in radiation, surgery, pathology and medical oncology with substantial practices in prostate cancer.)

To me, this article is in the "must read" category for recently diagnised patients who are not going on active surveillance but instead are chosing a therapy with intent to cure. An alternative is to check with the Prostate Cancer Treatment Center for the source publication, but the article gives some additional insights and does a very nice job of explaining how the group screened more than 18,000 articles and boiled them down to 848 studies about treatment, and then into just 140 studies that met their criteria to ensure quality and comparability. For instance 21% of studies of EBRT were rejected because an obsolete dose below 72 Gy was used (with 78-82 Gy being commonly used today for EBRT); many studies from all therapy types were rejected because there were fewer than five years of follow-up or fewer than 100 patients.

The article provides three key tables by risk level, using well-recognized standards for risk: low-risk, intermediate-risk, and high-risk. Each table shows the studies of various therapies by symbols, and you can quickly see the success rate - freedom from PSA failure - for each study and the average time of follow-up for the study. Moreover, circles that encompass most of the results for brachy (purple circle), surgery (red circle) and EBRT (green circle) give you a quick appreciation where most of the results fall. Each symbol also has a number that allows you to track it to the specific source study, though it takes another step or two to get that infomation.

For instance, the small blue circle for study 27 in the low risk table is for a brachytherapy study with a success rate of about 98% (! ) with about 11 1/2 years of average follow-up (! ), which is more than any other study for any of the therapies reported. The new, long-awaited result for proton therapy is also there, showing an impressive success rate of about 95% at an average follow-up of about 9 years. The tables for intermediate- and high-risk patients are equally illuminating, showing how some approaches notch impressive results that are durable while other approaches are shaky choices at best.

But there's more! The other side of the treatment-choice coin is side efffects, and the article couples the success-rate tables with tables for each of four major side-effects: A. Sexual Dysfunction, B. Bowel Problems, C. Urinary Continence, and D. Urinary Obstruction/Irritation. For sexual and urinary obstruction/irritation the tables have three subtables, showing normal, intermediate and poor baseline performance before treatment. Then post-treatment at three year results are shown for RP, EBRT, or brachytherapy, with nerve-sparing and non-nerve sparing shown separately for surgery. Results graphically display post-treatment results divided into normal, intermediate and poor post-treatment performance, each clearly defined. The tables for bowel and urinary continence divide the groups into just two baseline levels: normal and intermediate.

Here's my own summary interpretation of all the tables, though it's important to keep in mind that this is just one study, though it appears to have been very well done: brachytherapy, with clear superiority in prostate cancer success, has a striking advantage in sexual function and is clearly superior to RP in urinary continence, and only slightly poorer than RP in urinary obstruction/irritation, with bowel issues the only area of clear and substantial inferiority to RP; however, even in the bowel area, there is only an 8% difference in the percentages of men with poor performance between men with normal function at the start. On the whole, poor performance after treatment is not a huge problem on average for any of the approaches except for sexual function for RP and EBRT for men who were normal at the start, and most intermediate baseline men do quite well except for sexual function for surgery, EBRT, and brachytherapy.

Last edited by IADT3since2000; 06-13-2011 at 10:41 AM. Reason: added PCRI abbreviation; spelling

 
Old 06-13-2011, 10:46 AM   #3
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

More and more, Jim, I keep coming back to your thoughts on surgery where Irv's case was concerned....before he had the surgery. I sensed it, even though you didn't come right out and say it.

It's really a tough call because, for him, clearly most of the cancer was in his prostate. His prostate had practically turned into one large tumour with 80% of it found to be cancerous. So, in that regard, it felt good to debulk it and get rid of the main source of the problem.

On the other hand, the main side effect, which is ED, could be permanent. The fact that he's on hormone therapy now just exacerbates that problem.

We always tend to question our decisions....to have surgery, or not to have surgery? To radiate or not to radiate? Avodart or no Avodart?

I just wish there was an easy answer.

Rhonda

Last edited by honda50; 06-13-2011 at 10:47 AM.

 
Old 06-13-2011, 03:24 PM   #4
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

Jim,
I read the study when it first appeared. The only criticisms I have seen is from other posters who call it a biased radiation study that was never published in a medical journal. I have seen no contrary comments from doctors, especially surgeons who I expected would have a reaction to the Study's results.
JohnT

 
Old 06-13-2011, 07:10 PM   #5
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

While I applaud them for trying to make those comparisons, there are three glaring omissions that are probably the most successful treatments now available. The two problems with radiation have always been (1) not enough radiation and (2) damaging cancer cells beyond possibility of recovery.

#1, not enough radiation, has been solved with IGRT/IMRT external beams, protons and with brachy by delivering more radiation while controlling the dose to healthy tissues. It is limited in external beam by significant bladder and rectal toxicity when delivering more than about 80 Gy.

#2, damaging cancer cells beyond possibility of recovery is more problematic. As we've learned in the past five years, prostate cancer cells seem to be unique in that they have what's called a low alpha/beta ratio (it is now recognized to be around 1.5). This means they can recover almost as well as healthy cells from small doses of radiation spread out over a long period of time. EBRT, typically around 2 Gy a day for about 8 weeks, allows some cancer cells to get knocked down temporarily and go into a self-protective mode until the radiation danger has passed. This is especially true of cancer stem cells. LDR brachy (seeds) does a better job by delivering a much higher dose, especially in the first few weeks, so that the cell kill is more complete. BTW, the results at U of W Seattle seem to be much better than anywhere else in the country -- the results in the study seem to be skewed by that.

There have been two innovative solutions to the problem of the low alpha/beta ratio. HDR Brachytherapy (temporary seeds) and CyberKnife. HDR Brachy had been around for a long time as a boost to EBRT, but more recently has been used as a monotherapy with great results. It involves the temporary insertion of very highly radioactive needles into the prostate (through the anaesthetized perineum). It delivers a lot of radiation very quickly and very accurately. In the most recent study, it gave 97% biochemical control after 5 years (99% metastasis-free) with less than 1% long-term urinary and no long-term rectal problems.

The other innovation, CyberKnife, was created in an attempt to duplicate the results of HDR Brachy. It deals with the problem of the low alpha/beta by using "hypofractionation" - very large doses delivered in just a few fractions, typically four or five visits. It is able to achieve this without significant toxicity to the bladder or rectum by using a technique known as stereotaxis -- the radiation hits the prostate from all sides until the cumulative dose is achieved. Some centers deliver 10 Gy in 4 treatments (40Gy total) which is biologically equivalent to a dose of 131 Gy if delivered by IMRT 2 Gy at a time -- an effective dose escalation of 64%.The five year result showed 94% biochemical control with only 2.5% long-term urinary effects and no long-term rectal effects.

The latest solution, pencil-beam protons with IMRT solves the problem in a different way. Protons have about ten times the cell kill of X-rays. This new technology allows a very controlled beam of protons that conforms to the shape of the prostate, and it isn't spread around the way the old technology did it, but is intensely localized instead. New centers with this technology have just started to come online, so there are no long-term results as yet. However, it is in every way an improvement over the old technology, which had good results.

I should mention that in Japan and Germany, carbon-ion radiation therapy is now available. One would expect it to have even better results than proton therapy, because the cell kill of the much bigger carbon ion is many times greater. Less toxicity too, because there is no problem of secondary neutrons.

- Allen

 
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Old 06-14-2011, 05:47 AM   #6
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

Good morning Allen,

The Prostate Cancer Results Study Group is simply reporting what is out there in research published in respected, peer reviewed journals, research which meets a number of reasonable criteria, and they are including new studies that satisfy the criteria as they come along. I suspect that CK SBRT (CyberKnife with Stereotactic Body Radiotherapy) has not had sufficient size, or length with patients stratified to standards. It would be interesting to check that out.

However, as good as that is and as good as the other approaches you note may be, hopefully living up to our hopes when research is published, it's going to be very hard to top the brachytherapy results at leading centers in my opinion. I am encouraged not just by the now long-term brachy results, but also by the earlier very high success rate results - high nineties - that have a flat line for failure around the five year point. In other words, there are very few failures for men who achieve PSA control - probable cure - to that point. I have not looked at the study sources yet, but I'll bet that the Dattoli Center studies are also in that very high scoring group, and perhaps studies from other centers. To me, those fine results are showing that problems (1) and (2) that you mention below have been solved. If you can get the PCRI Insights newsletter, also take a look at Nathan Roundy's editor's column. He highlights a study demonstrating that modern higher dose EBRT (external beam radiation therapy) is far more effective than older approaches which used lower doses. This is also evidence that problems (1) and (2) have been solved.

[QUOTE=Tall Allen;4777279]While I applaud them for trying to make those comparisons, there are three glaring omissions that are probably the most successful treatments now available. The two problems with radiation have always been (1) not enough radiation and (2) damaging cancer cells beyond possibility of recovery. The rectal toxicity, per the other half of the Grimm article I addressed in the first post, is reasonably low, in my view, for radiation in the modern dose EBRT range of about 78-82 Gy. Along the same line of thinking, the PCRSG also shows numerous studies that I believe demonstrate the alpha/beta ratio is not a problem for brachytherapy, specifically including non-high-dose-rate (non-HDR) brachytherapy, which makes sense as a far higher radiation dose is delivered at one time and then gradually decreases. Perhaps the ratio issue is why most EBRT studies are not showing success in the 90s, with even the new proton study not showing success in the high 90s.

All that said, I'm looking forward to further achievements, and they well may come from the developments you describe.

Your thoughts?

Jim

 
Old 06-14-2011, 05:58 AM   #7
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

Hi John,

You wrote:


Quote:
Originally Posted by Johnt1 View Post
Jim,
I read the study when it first appeared. The only criticisms I have seen is from other posters who call it a biased radiation study that was never published in a medical journal. I have seen no contrary comments from doctors, especially surgeons who I expected would have a reaction to the Study's results.
JohnT
I too have a concern with bias as a brachytherapy center is the leading sponsor of the study. However, the group of experts looked representative and truly expert to me, enough to challenge studies that did not meet reasonable criteria that they established. Moreover, all of their work and the basis for it are highly visible: any of us could search PubMed and come up with the same tables if we wanted to spend the time. I consider the key contribution of the experts to be the criteria that equaled the playing field with surgery, mainly by insisting that surgery studies would not count if they plucked out higher risk men who were found to be higher risk by post surgery pathology (editor Nathan Roundy notes this in his editor's column), and by not counting any of the studies with a now obsolete, too low level of radiation. They still are allowing, as I see it, one "unfair" advantage for surgery: they do not rule out follow-up radiation, which will naturally boost surgery success rates, as it is common for surgery failure but surgery after RT is most uncommon.

I too hope the study will be published in a respected medical journal. However, it will encounter some medical cultural headwinds, both from those who favor surgery or some other non-brachytherapy approach, and from those who are wedded to expensive, long-term, Phase III clinical trials as the only acceptable evidence.

My thoughts.

Take care,

Jim

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Old 06-14-2011, 07:30 AM   #8
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

Hi Rhonda,

I was rereading Dr. Myer's book over the weekend and came across a discussion of the surgery option for patients whose cancer has spread outside the prostate. He is in favor of it because of findings that hormone-resistance usually starts in the prostate rather than other sites of cancer, so removing the prostate may delay hormone refractory cancer.

Thought you might find this of some interest.

Best wishes,
Tom

 
Old 06-14-2011, 11:20 AM   #9
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

I am also encouraged by all reports of results in the 90s for freedom from biochemical failure. Looking at the results of low dose rate brachy, I've found the results to be all over the map, though. Seed implantation is probably one of the most skill-dependent of the radiation procedures. The American College of Radiology (Apr 2011) said in their report that as brachytherapy followups have matured, it has become increasingly apparent that efficacy and morbidity are highly dependent on implant quality. They further state that continued attempts to refine patient selection, brachytherapy treatment planning philosophy, technique, and postimplant management should result in further improvements in biochemical outcome and decreased brachytherapy-related morbidity.

It seems that there are centers that do very well with it, but many who achieve results in the 80s or less in terms of freedom from biochemical failure. The Journal of the American Society of Brachytherapy last year reported that the dose given during implantation can have as much as a twenty point difference in achieving control. Those who were implanted with at least 147 Gy on the day of the implant, achieved control of 94%, while those who were implanted with less than 147 Gy on the day of the implant achieved control in only 75% of the cases. I stress "on the day of the implant" because, as it turns out, that seems to be a difficult parameter to measure. I125 has a half-life of 59 days, which spreads the dose over a fairly long period. Also, its radiation spreads out in all directions, making it difficult to control toxicity to the rectum, bladder, etc., which is why correct placement is so critical.

This finding is very much in line with the low alpha/beta for prostate cancer tissue and the need to deliver a very high dose rate all at once in order to effect a very high cancer cell kill without chance of recuperation. Hopefully, as experience and standards improve, everyone will achieve durable cures with seeds.

- Allen

 
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Old 06-15-2011, 06:02 AM   #10
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

Hi Allen,

I believe you have summarized the status of brachytherapy very well, with some centers achieving outstanding results but others, as you put it, all over the map:


Quote:
Originally Posted by Tall Allen View Post
... Looking at the results of low dose rate brachy, I've found the results to be all over the map, though. Seed implantation is probably one of the most skill-dependent of the radiation procedures. The American College of Radiology (Apr 2011) said in their report that as brachytherapy followups have matured, it has become increasingly apparent that efficacy and morbidity are highly dependent on implant quality. They further state that continued attempts to refine patient selection, brachytherapy treatment planning philosophy, technique, and postimplant management should result in further improvements in biochemical outcome and decreased brachytherapy-related morbidity.

It seems that there are centers that do very well with it, but many who achieve results in the 80s or less in terms of freedom from biochemical failure...
We had a well-regarded local radiation oncologist present to our support group last night, and he made several statements and answered several questions right on this issue. He had had substantial supervised training in brachy over a period of time, but he told us of other doctors he knew who had had just a weekend course and then were on their own. He also told us of lack of consensus even among the experts on the best seed placement tactics, describing a number of available approaches, not to mention the choice for isotopes.

I'm thinking that a low-risk patient who is well qualified for a number of therapies will do best if he is treated by brachytherapy at a center of proven excellence, if the patient is comfortable with brachytherapy. If not, then finding the best doctor available, no matter which of the therapies he uses, is probably the best course. Our speaker stressed the importance of peace of mind, and he was convinced that that was best achieved when the patient believed in the therapy he was getting, even if his choice was not favored by reserch.

I learned something about the dose for brachy but do not fully understand it, and perhaps you can look into it. Doses for brachy are always far higher than for other forms of radiation. For instance, you mention the importance of a dose of 147 Gy, which contrasts to modern dose ranges of about 78 - 82 Gy for external beam radiation. However, the speaker said that that is the dose measured for the seeds and that the actual, impacting bio-available dose is much lower.

Regarding CyberKnife Stereotactic Body Radiotherapy (CK SBRT) by the way, his colleague, who does not practice with CK or SBRT, had just attended a users' goup conference and had come away very impressed, calling the data presented "compelling". He had seen an abstract of five-year data from Georgetown U. that adds to the previous report with five-year average follow-up. (Do you know about the Georgetown research?) Our speaker said he personally still considers CK SBRT "experimental," but it is clear that his view has been becoming rapidly more favorable and accepting over the course of the past three years in his annual presentations to us.

Take care,

Jim

 
Old 06-16-2011, 09:19 PM   #11
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Re: Choosing a therapy - lessons from the Prostate Cancer Results Study Group

Hi Jim,

Quote:
I learned something about the dose for brachy but do not fully understand it, and perhaps you can look into it. Doses for brachy are always far higher than for other forms of radiation. For instance, you mention the importance of a dose of 147 Gy, which contrasts to modern dose ranges of about 78 - 82 Gy for external beam radiation. However, the speaker said that that is the dose measured for the seeds and that the actual, impacting bio-available dose is much lower.

Comparing these are especially difficult without graphs and a lot of equations, but I can at least mention some of the factors involved. The first, as I mentioned is the biologically equivalent dose (BED).

BED=n*d (1+d/ (α/β))

n=# of fractions, d=dose/fraction, α/β=alpha/beta ratio
So the biological effect increases inversely with the alpha/beta ratio, geometrically with the dose per fraction, and linearly with the # of fractions.

With seeds, the other major effect is the exponential decay of radioactivity. Let's say that you get fresh I125 seeds delivering .08Gy/hr initially. That would give you 1.92 Gy on the first day, 1.90 Gy on the second day, .81 Gy on the 59th day, and .026 Gy on the 365th day. Cumulatively, by the 365th day, you've received 160 Gy dose from your seeds. If the alpha/beta is 1.5 (current best estimate), this dose is only about 10% greater on a bioequivalent basis to an 80 Gy dose given as 2 Gy/day for 40 days by IMRT. Its effect is further reduced by a repopulation effect: the cells most of the year can repopulate faster than they are destroyed because the dose per day gets so low, especially to the late-responding tissue like PC. However, it is increased somewhat too because the relative biological effectiveness of a weak emitter like I125 is high because the ionizing electrons do not reach beyond the prostate. In net, what appears to be 160 Gy is biologically much less than 88 Gy.

For comparison, Dr. Fuller in San Diego is currently using CyberKnife to deliver doses of 10 Gy in 4 fractions. This would be equivalent to a dose of 131 Gy if given as 2 Gy/day by IMRT.

It is my impression that the better centers place more seeds and are better at keeping them away from the urethra, bladder and rectum.

- Allen

 
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