New RT treatment

User

Posted 30 Sep 2023 at 08:12

What does everyone think of this?

https://www.bbc.co.uk/news/health-66946336

Looks potentially exciting!!

User

Posted 30 Sep 2023 at 13:38

Same story in another thread here https://community.prostatecanceruk.org/posts/t29796-Radio-therapy-rethink

Edited by member 30 Sep 2023 at 13:39 | Reason: to highlight link

Barry

User

Posted 03 Oct 2023 at 10:31

Originally Posted by: Online Community Member

Think I’ve seen in uk standard until now has been 20 days,but in USA standard is 40 days?

The original standard for most external beam radiotherapy is 37 fractions of 2 Gy each, making 74Gy. There's a little variation between centres, but the US has always been higher because of the way their healthcare system works (they make more money from more fractions). 37 was a good compromise between curing the cancer and not inflicting serious damage on non-cancerous tissues. For a long time, this was used for all cancers treated with external beam radiotherapy.

It was subsequently found that prostate cancer actually treats better with higher doses over a shorter length of time. This is called hypofractionation, and is 20 fractions of 3Gy each, making 60Gy. Due to the higher dose rate and shorter duration of the treatment, this has the same treatment effect as the original 74Gy.

This reduction in fractions and higher dose rate (hypofractionation) combined with the capability to better mask/aim the beam has been taken further to the treatment being discussed. Some slightly different formats have been tried and I'm not sure if any one has been settled on, but one I came across was 5 fractions of 7.5Gy each, making 37.5Gy. Many other body tissues cannot take doses this high (the prostate is unusual in this respect), which means the aiming and masking has to be more accurate, something which improvements in LINACs can now achieve. By the way, this is not new - the trial has been going 11 years. What is new is that long term data is now available confirming it is effective.

There have also been some trials of just 2 fractions.

I don't know the situation with hypofractionation in the US now, but certainly it was lagging a long way behind other countries, again almost certainly driven by it not being as profitable.

Edited by member 03 Oct 2023 at 10:38 | Reason: Not specified

User

Posted 03 Oct 2023 at 02:39

Greater accuracy becomes increasingly important with heavier doses of Photons or Hadron treatment. I had a combination of both (30 fractions of 2 Gy IMRT plus 6 fractions of 3 Gy Carbon Ion where the RBG of the latter is approximately 3 times that of Photons). The accuracy was considered so important that I was given an MRI and 5 CT scans in a week, plus had a body mold made covering head to knees that was bonded to a wooden frame which was in turn bolted to the treatment table for every fraction. The fiberglass like suit had been cut in half and I had to climb into it and then it was secured by plastic fixings. However, the molded suit was so tight a fit that I could not move and the alignment marks were on the suit so no tattoos required. That was some prerequisite!

Barry

User

Posted 03 Oct 2023 at 14:09

Nick,

They gave up trying to get me to the high accuracy requirements needed for Prostate SABR and so I was moved to 20 day standard. It wasn’t my choice.

1 day to go😊

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User

Posted 30 Sep 2023 at 13:38

Same story in another thread here https://community.prostatecanceruk.org/posts/t29796-Radio-therapy-rethink

Edited by member 30 Sep 2023 at 13:39 | Reason: to highlight link

Barry

User

Posted 02 Oct 2023 at 15:56

The media reports look good, however they have omitted the substantial setting up measurement scan hurdle that has to be surmounted first. I was headed for 5 day SABR, however failed, on 4 separate occasions to achieve a successful measurement scan which apparently is more rigorous than the standard 20 day version which I am now close to completing. The extra accuracy requirement was quite stressful. The two types I’m told achieve the same end result, but the 20 day version has less risk for adverse side effects later, so I’m probably better off.

User

Posted 02 Oct 2023 at 16:27

Can't seem to get my head around why the hormone therapy is no longer required 😲

User

Posted 02 Oct 2023 at 18:16

Scotti, I didn’t know about the more complex setup. What’s the procedure?

User

Posted 02 Oct 2023 at 19:41

Nick,

Measurement attempt planning ct scan just the same, but acceptance criteria tighter. ( in Plymouth). Also I believe not everywhere possesses the more accurate machine needed.

So the more rigorous full at the front, empty at the back requirement for SABR (5 day, rather than 20 day) measurement scan personally I never managed to achieve, despite having to return on 4 separate occasions. I believe the 5 day SABR is higher daily dose, more accurate, more powerful multi beam delivery, that needs you and your organs to be absolutely accurately positioned to guarantee not hitting the wrong spots. Apparently the standard 20 day RT in Uk positioning standard is slightly less rigorous, and therefore less stressful. I found the right configuration very difficult to achieve front and back, and pretty stressful for some reason - possibly previous medical history?

I don’t think everyone’s post biopsy outcome is suitable for the SABR route, perhaps just a few? Mine was. When I was told I was heading for 5 days RT I was pretty happy, I was expecting 20, but a suspect I’ve had a better (and more expensive) outcome in the end. 2 more RT days to go, then happy to end HT pills also, just final jab in couple of months.

Think I’ve seen in uk standard until now has been 20 days, but in USA standard is 40 days?

User

Posted 02 Oct 2023 at 21:53

Thanks Scotti,

So did you choose to change to 20 days? Or because you struggled to get the front and back business sorted?

glad to hear you’re almost there with it. Must be a relief.
cheers

User

Posted 02 Oct 2023 at 22:51

Originally Posted by: Online Community Member

Can't seem to get my head around why the hormone therapy is no longer required 😲

There are lots of reasons for using hormone therapy. For the lower power radiotherapy doses (external beam and LDR brachy), it makes the radiotherapy work better. However, for the higher power radiotherapy doses (HDR brachy and SABR), it is not so useful in that respect, but might be used for other reasons in some cases.

User

Posted 03 Oct 2023 at 02:39

Barry

User

Posted 03 Oct 2023 at 05:27

Barry,

I haven’t heard of that sort of contraption before (apart from a good friend’s daughter who needed one for proton beam therapy on a brain tumour in the States). Was it recent? So they still do that?

User

Posted 03 Oct 2023 at 10:31

Originally Posted by: Online Community Member

Think I’ve seen in uk standard until now has been 20 days,but in USA standard is 40 days?

I don't know the situation with hypofractionation in the US now, but certainly it was lagging a long way behind other countries, again almost certainly driven by it not being as profitable.

Edited by member 03 Oct 2023 at 10:38 | Reason: Not specified

User

Posted 03 Oct 2023 at 14:09

Nick,

They gave up trying to get me to the high accuracy requirements needed for Prostate SABR and so I was moved to 20 day standard. It wasn’t my choice.

1 day to go😊

User

Posted 03 Oct 2023 at 15:09

Hi Nick,

They used to send patients, especially children from the UK to the USA for Proton Beam to the head which was a very expensive exercise but this treatment (which is another form of Hadron therapy, can now be done at The Christie in Manchester or at UCLH in London where each have a cyclotron.) For Carbon Ions you need a synchrotron which is much bigger and more expensive. This is the one I was to be treated on in Heidelberg in 2008 as part of a study but in the event the software was not ready until 2009, so I had my 6 fractions as part of a trial at GSI Darmstadt which has or had an even larger synchrotron but lacked a gantry. The dose was delivered from two angles which interestingly they continued for Prostate Cancer even after the trial was transferred to Heidelberg where there wide choice of angles.. Unfortunately, this forum will not permit me to show photographs of the full body cast I wore but you can see the head part in a clip in video. It took 70 engineers and staff to run and service this machine which uses enough power to supply a small town of 10,000 people So not surprising costs vast. Like everything else the system was made more compact for the next one that was built in Italy, but still very expensive even though Carbon Ions pack much more of a punch then Photons or Protons. I think the result of the study for Prostate gave pretty good results but at considerable cost. I was lucky to get it for free.

They are still treating at HIT as far as I am aware but the study I took part in has been over for a long time now.

https://www.youtube.com/watch?v=LeApaY7ctMo

https://www.youtube.com/watch?v=2cRYaIJ

Barry

User

Posted 03 Oct 2023 at 21:40

I think Andy makes a good point. The higher individual doses need higher positional accuracy, and that depends on the latest generation of radiotherapy machines which have only relatively recently begun to be rolled out across the country (major research centres got them earlier).

That they didn't require HT is interesting. From a biological point of view there is likely to be a benefit of not having cells at different stages of division when irradiating, so with low to medium risk prostate cancer having a doubling time of around 6 months means HT for 6 months to "freeze" division, but not as clear a rationale for continuing HT after radio (the situation is different for high risk PC where there is less confidence radio will eliminate most cancer cells). However if the clinical trials showed the new dosage worked without HT that is brilliant, for most of us it is the HT that becomes hardest to endure.

User

Posted 04 Oct 2023 at 06:49

Barry,

Thanks for the explanation. I wasn’t expecting it to be so enormous! Presumably why the presenter was from CERN.

I managed to develop a bit of claustrophobia during my scans so the full body cage gives me sweaty palms. Hats off for getting inside!

Nick

User

Posted 04 Oct 2023 at 09:50

Originally Posted by: Online Community Member

but not as clear a rationale for continuing HT after radio (the situation is different for high risk PC where there is less confidence radio will eliminate most cancer cells). However if the clinical trials showed the new dosage worked without HT that is brilliant, for most of us it is the HT that becomes hardest to endure.

An additional factor for the use of longer term hormone therapy is the chances of micro-mets outside the treated area. Hormone therapy combined with loss of the primary tumours is thought to result in micro-mets dying too, reducing the chance of recurrence outside the treated area. The SABR/SBRT has a sharp cutoff (compared with standard external beam radiotherapy), and that's why this case is only suitable where the diagnosis is low enough risk to be sure as possible there are no micro-mets. With standard external beam radiotherapy, both the beam spill outside the primary target treatment area into the area where undetected spread is most likely and the hormone therapy will mop up micro-mets outside the primary target treatment area.

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