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What is the maximum radiation dose you can receive treating prostate cancer before it significantly

User
Posted 01 Aug 2021 at 19:57

Keep thinking that if you get radiation as first treatment and then mets occur and you have to get more salvage radiation... how much radiation can the body take? When does it get risky?

If you get surgery, you are still not radiated, so you have radiation in your arsenal.

Any advice would be much appreciated.

________________________

59M, Gleason 4+3, PSA7.8, T2C.

DaVinci Surgery or HDR Brachytherapy+EBRT or Cyberknife(SBRT)?

User
Posted 02 Aug 2021 at 00:28
You can't have salvage RT to the area that has already been treated with RT. Whether you have EBRT over 37 fractions (74Gy) or 20 fractions (60 or 64Gy) or EBRT with brachy, that's it for the pelvis.

It is sometimes possible to have RT to distant mets not in the pelvic area, or possibly some salvage HIFU to an irradiated prostate.

"Life can only be understood backwards; but it must be lived forwards." Soren Kierkegaard

User
Posted 02 Aug 2021 at 00:56

Radiation can cause adverse problems even with the normal amount generally given in a country using a combination of a number of fractions (sessions) and number of Grays of radiation administered at each fraction. There is always a risk as experienced here https://community.prostatecanceruk.org/posts/t27479-Any-treatments-for-me

In some countries or in trials a man may be given a higher dose than is usual in the UK, I had a higher dose in Germany. More radiation can improve effectiveness but with the increasing risk of greater damage to other organs such as the bowel. So the amount of radiation originally given and the paths it took can affect the amount of radiation given as a follow up to specifically treat a few metastases. To get a definitive answer you will need to discuss this with a radio oncologist who will need to know about your previous RT and a number of other things. This is theoretical at present as you have not had RT or had mets diagnosed. So there is no set point where RT becomes 'risky' but more RT means greater risk of associated problems. The radio oncologist will decide the limit of radiation an individual will be given in countries where there is not a set limit.

Certainly where Prostatectomy has not got all the cancer, many men have follow up RT, but then you risk adding to the side effects with those of another treatment and quite likely HT too. It's not an easy decision as you can make a case for and against each treatment, but at the end of the day it really is one that you have to make taking into account what your clinicians tell you and how you feel

Edited by member 02 Aug 2021 at 00:59  | Reason: Not specified

Barry
User
Posted 04 Aug 2021 at 18:45
Glad you've made a decision. Best of luck with the surgery.

Chris

User
Posted 04 Aug 2021 at 22:34
Well you have looked into this as well as you can as a non professional and probably more than most. Interested to learn it has gone well for you in due course.

Many men feel a sense of relief having made their treatment decision and I hope this is the case with you.

Barry
User
Posted 15 Aug 2021 at 21:50

You are pretty much the same as me. Diagnosed at 57. 4+3. PSA 8.2

I opted for surgery in the end June 2020. Final Gleeson 4+3. Cancer more extensive and had positive margins with a little on the bottom of my bladder. I'm glad the entire prostate is gone for this reason.

Started HT Dec 2020. RT end Dec 2020/Jan 2021. Urinary and bowel function are generally good. 

No labido and have ED. Will be on HT until Dec 2022. 

Best wishes. 👍

Jim

 

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User
Posted 02 Aug 2021 at 00:28
You can't have salvage RT to the area that has already been treated with RT. Whether you have EBRT over 37 fractions (74Gy) or 20 fractions (60 or 64Gy) or EBRT with brachy, that's it for the pelvis.

It is sometimes possible to have RT to distant mets not in the pelvic area, or possibly some salvage HIFU to an irradiated prostate.

"Life can only be understood backwards; but it must be lived forwards." Soren Kierkegaard

User
Posted 02 Aug 2021 at 00:56

Radiation can cause adverse problems even with the normal amount generally given in a country using a combination of a number of fractions (sessions) and number of Grays of radiation administered at each fraction. There is always a risk as experienced here https://community.prostatecanceruk.org/posts/t27479-Any-treatments-for-me

In some countries or in trials a man may be given a higher dose than is usual in the UK, I had a higher dose in Germany. More radiation can improve effectiveness but with the increasing risk of greater damage to other organs such as the bowel. So the amount of radiation originally given and the paths it took can affect the amount of radiation given as a follow up to specifically treat a few metastases. To get a definitive answer you will need to discuss this with a radio oncologist who will need to know about your previous RT and a number of other things. This is theoretical at present as you have not had RT or had mets diagnosed. So there is no set point where RT becomes 'risky' but more RT means greater risk of associated problems. The radio oncologist will decide the limit of radiation an individual will be given in countries where there is not a set limit.

Certainly where Prostatectomy has not got all the cancer, many men have follow up RT, but then you risk adding to the side effects with those of another treatment and quite likely HT too. It's not an easy decision as you can make a case for and against each treatment, but at the end of the day it really is one that you have to make taking into account what your clinicians tell you and how you feel

Edited by member 02 Aug 2021 at 00:59  | Reason: Not specified

Barry
User
Posted 04 Aug 2021 at 17:02

Thats it. I'm going with surgery. Thank you for all the information you have provided.

________________________

59M, Gleason 4+3, PSA7.8, T2C.

DaVinci Surgery or HDR Brachytherapy+EBRT or Cyberknife(SBRT)?

User
Posted 04 Aug 2021 at 18:45
Glad you've made a decision. Best of luck with the surgery.

Chris

User
Posted 04 Aug 2021 at 22:34
Well you have looked into this as well as you can as a non professional and probably more than most. Interested to learn it has gone well for you in due course.

Many men feel a sense of relief having made their treatment decision and I hope this is the case with you.

Barry
User
Posted 05 Aug 2021 at 08:19

Originally Posted by: Online Community Member
Well you have looked into this as well as you can as a non professional and probably more than most. Interested to learn it has gone well for you in due course.

Many men feel a sense of relief having made their treatment decision and I hope this is the case with you.

Yes, surgery is decision because of age 59.

If you are 85,88, you don't really worry about potential radiation issues 10 years down the line. Different story if you are 59.

________________________

59M, Gleason 4+3, PSA7.8, T2C.

DaVinci Surgery or HDR Brachytherapy+EBRT or Cyberknife(SBRT)?

User
Posted 05 Aug 2021 at 08:54

Just to add that the unit that measures the amount of radiation absorbed into a volume of tissue is the Gray (Gy). However, this doesn't by itself give you the biological effect (BE), because that also depends on the rate at which the radiation is delivered. Radiation delivered at a high power over a short duration has much more BE than the same dose delivered slowly over a long time.

LDR brachytherapy using Iodine125 is 150-170Gy over ~28 weeks.
The classic external beam radiotherapy dose is 37 x 2Gy = 74Gy over 7½weeks.
Hypofractionated external beam radiotherapy dose is 20 x 3Gy = 60Gy over 4 weeks.
Ultrahypofractionated external beam radiotherapy dose is 5 x 7½Gy = 37½Gy over <2weeks.
HDR Brachy monotherapy (rare in the UK) is 2 x 15Gy = 30Gy over 2 weeks.

So here we see a variation between 170Gy and 30Gy over different durations, but the BE is roughly the same in all cases. I don't know of any units for BE, but basically, you get given the max lifetime BE, that being most likely to cure the cancer without doing you excessive collateral damage. That's the reason you can't have it more than once to the same tissue.

When radiotherapy fails, it most often fails outside the target area because the cancer had unknowingly already escaped. These areas can often be retreated providing the spill of BE they received during the first radiotherapy treatment is low enough that they still have sufficient reserve from their max lifetime treatment to do a useful retreatment, and treatment plans can be constructed which don't take any other tissues over their max lifetime BE. This is more likely to be possible the further away the recurrence is from the original treatment site. Having said that, radiotherapy can occasionally fail in the original treatment volume, in which case curative options might be salvage prostatectomy or one of the focal treatments.

User
Posted 13 Aug 2021 at 09:25

Im sure you've made the right decision for you and wish you best of luck. 

User
Posted 15 Aug 2021 at 21:50

You are pretty much the same as me. Diagnosed at 57. 4+3. PSA 8.2

I opted for surgery in the end June 2020. Final Gleeson 4+3. Cancer more extensive and had positive margins with a little on the bottom of my bladder. I'm glad the entire prostate is gone for this reason.

Started HT Dec 2020. RT end Dec 2020/Jan 2021. Urinary and bowel function are generally good. 

No labido and have ED. Will be on HT until Dec 2022. 

Best wishes. 👍

Jim

 

 
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