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User
Posted 31 Jul 2022 at 19:10

Hi, my first post, on Friday I saw an oncologist for the first time at The Christie after being diagnosed in early June with a gleason score of 4+3 and stage T2. I'm  67.The cancer is contained in the prostate. Had a weeks course of tablets in June to help shrink the prostate and then a hormone injection (Prostrap) for 1 month, I've now had the second Three monthly injection.


The oncologist recommended to stay on hormones for two years and to have 4 weeks RT in October, which seemed straightforward enough. I've been reading on this and other forums what to expect but then he threw me and my wife by talking about a trial called PIVOTALboost, A computer  randomly selects which arm of the trial your on. Either 1 Prostate IMRT or 2 Prostate IMRT+Bracotheraphy & No 3 Prostate & Pelvic IMRT+ Bracotheraphy, I've got the leaflet that explains and booklets on  Bracotheraphy but wondering  if anyone as done this trial and how they got on and how they think the trial is run. Any input on pelvic IMRT would be greatly appreciated.


I'm going to be phoned on Thur/Fri to tell them what I've decided, so thanking in advance anyone who can shed some light on this trial.


 


 


 

User
Posted 01 Aug 2022 at 20:15

I'm going to challenge the assertion that HDR Boost is increased treatment with increased toxicity.


My IMRT (or more strictly, IG-VMAT) was 23 x 2Gy which is 62% of the standard full IMRT/IG-VMAT non-hypofractionated dose to prostate, seminal vesicles, and pelvic lymph nodes. This is thought to be sufficient to mop up micro-mets.

Added to this is the HDR boost which was 1 x 15Gy to the prostate only (can include seminal vesicles too if known disease in them) which is 50% of the standard HDR dose (2 x 15Gy).


This means the tissues outside the prostate received 62% of the dose they would have with just IMRT/IG-VMAT, whereas the prostate itself received 112% of a standard dose (and maybe more, because I think a standard HDR monotherapy is a higher effective dose in any case than treatment with IMRT/IG-VMAT). You can't just compare the total Gy delivered, because higher power doses have a disproportionally higher effective treatment effect on the prostate.


Since many of the side effects come from radiating tissues outside the prostate (known as OAR - Organs At Risk), the hypothesis is the toxicity is lower with HDR boost. This is combined with delivering a higher dose inside the prostate where the cancer is. I was concerned with effect on erectile function, and my oncologist said they think HDR boost has a lower impact than standard IMRT/IG-VMAT, because of the lower levels of dose to the OAR.


We need to wait for the PIVOTALboost trial results which are probably years away before we know if this hypothesis holds, but this is the thinking of those clinicians performing the procedure today.

Edited by member 01 Aug 2022 at 20:18  | Reason: Not specified

User
Posted 31 Jul 2022 at 23:49

This thread is relevant to you.


https://community.prostatecanceruk.org/posts/t27094-PIVOTALboost-Trial


I was not on the trial but I did have IMRT plus Brachy and HT at the Christie.


If one arm of treatment was clearly better for you then that is what would have been offered. So you can assume that whichever arm you get selected for you will have as good an outcome as can be expected. However you will be advancing science for the next generation so personally I would volunteer for the trial.


 

Dave

User
Posted 01 Aug 2022 at 06:57
Dave I'm going to disagree, GLH has been offered plain IMRT (I think) if he is selected for a "Boost" arm he risks additional treatment toxicity for unproven benefit as that is the purpose of the trial.

User
Posted 01 Aug 2022 at 10:45

I was offered PIVOTALboost trial.


However, my onco thought it quite important I did the 3rd arm you mention including the pelvic lymph nodes, which he did according to the trial protocol, but not as part of the trial. (I think there are more variations on the 3rd arm, for different doses of the IMRT part - my recollection is there were 5 arms in total.)


My radiotherapy was 3 years ago, and so far I'm pleased with the results. It's too soon to know how well it worked, but looking OK so far. I was a high risk patient (due to PSA > 20 and staging > T2), and the 3rd arm you mention is considered to be a good compromise on hitting the cancer hard without excessive side effects, but also mopping up the areas where micro-mets (mets too small to show up on any scans) are most likely to be.


A couple of months back, I was able to tell my consultant I now can hardly tell anything was done, which is not at all what I was imagining at the outset. I do have a little rectal bleeding, but it has no impact on Quality of Life.


Several centres have been using this treatment protocol for some time with good results, but as francij1  correctly points out, until the PIVOTALboost trial reports, there haven't been any randomised control trials to provide the strict evidential comparisons.

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User
Posted 31 Jul 2022 at 23:49

This thread is relevant to you.


https://community.prostatecanceruk.org/posts/t27094-PIVOTALboost-Trial


I was not on the trial but I did have IMRT plus Brachy and HT at the Christie.


If one arm of treatment was clearly better for you then that is what would have been offered. So you can assume that whichever arm you get selected for you will have as good an outcome as can be expected. However you will be advancing science for the next generation so personally I would volunteer for the trial.


 

Dave

User
Posted 01 Aug 2022 at 06:57
Dave I'm going to disagree, GLH has been offered plain IMRT (I think) if he is selected for a "Boost" arm he risks additional treatment toxicity for unproven benefit as that is the purpose of the trial.

User
Posted 01 Aug 2022 at 10:45

I was offered PIVOTALboost trial.


However, my onco thought it quite important I did the 3rd arm you mention including the pelvic lymph nodes, which he did according to the trial protocol, but not as part of the trial. (I think there are more variations on the 3rd arm, for different doses of the IMRT part - my recollection is there were 5 arms in total.)


My radiotherapy was 3 years ago, and so far I'm pleased with the results. It's too soon to know how well it worked, but looking OK so far. I was a high risk patient (due to PSA > 20 and staging > T2), and the 3rd arm you mention is considered to be a good compromise on hitting the cancer hard without excessive side effects, but also mopping up the areas where micro-mets (mets too small to show up on any scans) are most likely to be.


A couple of months back, I was able to tell my consultant I now can hardly tell anything was done, which is not at all what I was imagining at the outset. I do have a little rectal bleeding, but it has no impact on Quality of Life.


Several centres have been using this treatment protocol for some time with good results, but as francij1  correctly points out, until the PIVOTALboost trial reports, there haven't been any randomised control trials to provide the strict evidential comparisons.

User
Posted 01 Aug 2022 at 13:23

Hi Francij , I agree he risks increased toxicity with increased treatment, but it also increases his chances of full remission by a few percent. 


I will suggest three gambling games. Game 1 you toss a coin and if it comes up heads you collect £2: game 2 roll a dice if you roll 6 collect £6: game 3 you draw a card from a 52 card pack if you draw the Ace of Spade you collect £52.


If you play either game 1000 times on average you will have £1000 winnings. GLH is being offered these three games. Based on current knowledge the risk reward ratio is the same. The doctors are trying to find if the coin, dice, cards are truly fair, and if not which gives the better average result.


For GLH based on current knowledge it makes no difference to his outcome. Nearly all people presented with cancer take the high risk high reward option, so a trial like this needs to be randomised to get people to take the equally good low risk options.

Dave

User
Posted 01 Aug 2022 at 20:15

I'm going to challenge the assertion that HDR Boost is increased treatment with increased toxicity.


My IMRT (or more strictly, IG-VMAT) was 23 x 2Gy which is 62% of the standard full IMRT/IG-VMAT non-hypofractionated dose to prostate, seminal vesicles, and pelvic lymph nodes. This is thought to be sufficient to mop up micro-mets.

Added to this is the HDR boost which was 1 x 15Gy to the prostate only (can include seminal vesicles too if known disease in them) which is 50% of the standard HDR dose (2 x 15Gy).


This means the tissues outside the prostate received 62% of the dose they would have with just IMRT/IG-VMAT, whereas the prostate itself received 112% of a standard dose (and maybe more, because I think a standard HDR monotherapy is a higher effective dose in any case than treatment with IMRT/IG-VMAT). You can't just compare the total Gy delivered, because higher power doses have a disproportionally higher effective treatment effect on the prostate.


Since many of the side effects come from radiating tissues outside the prostate (known as OAR - Organs At Risk), the hypothesis is the toxicity is lower with HDR boost. This is combined with delivering a higher dose inside the prostate where the cancer is. I was concerned with effect on erectile function, and my oncologist said they think HDR boost has a lower impact than standard IMRT/IG-VMAT, because of the lower levels of dose to the OAR.


We need to wait for the PIVOTALboost trial results which are probably years away before we know if this hypothesis holds, but this is the thinking of those clinicians performing the procedure today.

Edited by member 01 Aug 2022 at 20:18  | Reason: Not specified

 
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