Why Hormone therapy AFTER radiotherapy ??

User

Posted 26 May 2022 at 12:23

I am just about to start radiotherapy of just 5 fractions on a MRLinac machine, which is also similar to Nanoknife (My diagnosis is Localised T2, Gleason 3+4, PSA 19)

I have had 3 months Hormone treatment with Zoladex. I'm now due for another 3 month implant, I am unsure if I want to have this done

I understand that the zoladex shrinks the prostate, therefore reducing the amount of radiotherapy needed to zap the tumour , but can anyone tell me what the benefit will be of still being on Zoladex for nearly 3 months AFTER radiotherapy has finished?

I have struggled to get a logical answer anywhere else. Also I have seen people posting that with similar numbers to mine, their consultant has said there was no need for any hormone treatment alongside the R.T.

Any comments would be gratefully received.

Steve.

Edited by member 26 May 2022 at 16:41 | Reason: Clarification

User

Posted 26 May 2022 at 19:06

Exactly so - the RT will not have an immediate impact on the majority of cancer cells - its job is to damage their DNA so that when they reproduce, they are already broken and don't create more cancer. The HT controls your cancer until the cells start dividing & killing themselves.

Also, I assume you are on the Momentum trial? If so, it is essential to the integrity of the trial that men are treated exactly in the way set out in the trial design as a huge part of the trial is comparing the side effects in the short, medium & long term.

Edited by member 26 May 2022 at 19:11 | Reason: Not specified

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

User

Posted 26 May 2022 at 20:10

Thanks Lyn. That makes sense.

It is very frustrating that until now been unable to get an explanation that makes sense to a non-medical person with a reasonable level of intelligence and an enquiring mind.

Cheers.

User

Posted 26 May 2022 at 22:08

Basically, Steve, the way RT works is to damage the DNA of all the cells in the target area, both normal cells and cancer cells. Normal cells can repair their DNA, but in cancer cells the repair mechanism is usually broken, so eventually the cell dies. This can take up to 18 months to happen, which is why your PSA will typically reach a nadir (minimum) a year to 18 months after RT ends. The purpose of the HT is to prevent the cancer cells from reproducing while waiting for them to die.

Hope this helps,

Chris

User

Posted 27 May 2022 at 12:31

Originally Posted by: Online Community Member

The purpose of the HT is to prevent the cancer cells from reproducing while waiting for them to die.

Even having read the above [and other posts] I don't understand it.

I agree with you Jules, I still have not heard a satisfactory explanation, and I have looked.

As far as I understand it RT splits water molecules in cells this leaves free oxygen and hydrogen peroxide which disrupts the DNA. Healthy cells can repair this disruption cancer cells can't.

When the cell divides it unzips the DNA at this point it finds the zip is broken and the cell falls apart.

I cannot see where HT fits in to this mechanism to make it more effective. If anything it just delays the cells eventual death.

Obviously something else is happening but it is beyond my ken.

Dave

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User

Posted 26 May 2022 at 18:43

HT is usually continued after RT to help deal with any cancer cells missed by the radiation.

I can't understand from the little in your Profile/Bio why you are only having 5 fractions although perhaps they are each of higher dose.

Generally, men have 37 or 20 fractions as a main treatment, the latter at increased dose, except in cases where being treated alleviate pain perhaps a bone met or in addition to Brachytherapy. Maybe even fewer fractions at much higher dose being tried?

HT shrinks tumours and micro cancer cells rather than the Prostate.

Barry

User

Posted 26 May 2022 at 18:46

Hi Steve,

I’m sure someone else will come on to advise you better but from what I’ve read on here previously….my understanding is that it can take upto 18 months for RT to have been fully effective and so many are left on HT to keep things under control in that time.

User

Posted 26 May 2022 at 19:06

Edited by member 26 May 2022 at 19:11 | Reason: Not specified

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

User

Posted 26 May 2022 at 20:10

Thanks Lyn. That makes sense.

It is very frustrating that until now been unable to get an explanation that makes sense to a non-medical person with a reasonable level of intelligence and an enquiring mind.

Cheers.

User

Posted 26 May 2022 at 20:17

Thanks Barry.

I am on the "Momentum trial" which does give just five doses over a maximum of 14 days. The doses are higher, but given with a higher degree of accuracy (within approx 0.5mm) because of the machine used

Thanks for your comments

Steve

User

Posted 26 May 2022 at 22:08

Hope this helps,

Chris

User

Posted 26 May 2022 at 23:28

Thanks Chris.

I can't understand why it is so difficult for the medical profession to explain things in terms that an average person of reasonable intelligence can't understand.

I am not looking forward to extending the side effects of hormone therapy, but if I understand the logic behind it, then I am happier to accept it.

Thanks for your help and support.

Cheers. Steve.

User

Posted 27 May 2022 at 03:31

Originally Posted by: Online Community Member

The purpose of the HT is to prevent the cancer cells from reproducing while waiting for them to die.

Even having read the above [and other posts] I don't understand it.

Surely if the DNA of a cell is damaged it will be unable to reproduce as an evil cancer cell and if a cell isn't damaged then ADT can only hold the progression until it stops.

Regardless of the mechanism, for high risk cancer treated with RT followed by HT the measurable results of ADT are that 18 months of treatment give a better chance of survival than 6 months and that 2 or 3 years only slightly improves on 18 months.

Jules

User

Posted 27 May 2022 at 10:57

Thanks for your comments Jules.

Fortunately I am only classed as intermediate risk, so I am going to go with the 6 months, and keep fingers crossed!

User

Posted 27 May 2022 at 12:31

Originally Posted by: Online Community Member

The purpose of the HT is to prevent the cancer cells from reproducing while waiting for them to die.

Even having read the above [and other posts] I don't understand it.

I agree with you Jules, I still have not heard a satisfactory explanation, and I have looked.

As far as I understand it RT splits water molecules in cells this leaves free oxygen and hydrogen peroxide which disrupts the DNA. Healthy cells can repair this disruption cancer cells can't.

When the cell divides it unzips the DNA at this point it finds the zip is broken and the cell falls apart.

I cannot see where HT fits in to this mechanism to make it more effective. If anything it just delays the cells eventual death.

Obviously something else is happening but it is beyond my ken.

Dave

User

Posted 27 May 2022 at 15:02

Originally Posted by: Online Community Member

Agree with this but if RT only works for 18 - 24 months, that does not explain why patients are sometimes given HT for up to 3 years, although it seems to be being reduced in many cases as unnecessarily long. Experience has shown Oncologists that Adjuvant HT does help by starving the cells of Testosterone, weakening them in the process and improving the effectiveness of the RT. Just how this happens is academic. Where HT is continued indefinitely to slow spread, sooner or later any remaining cancer cells can find a way round lack of Testosterone.

Barry

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