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Radiotherapy with bilateral hip prosthesis

User
Posted 21 Aug 2024 at 12:53

Hello,

I’m hoping for some advice/answers on behalf of my Father In Law as hours/days of researching online hasn’t come up with much. 

A brief history - after being diagnosed with prostate cancer he had a successful prostatectomy a couple of years ago but has now just found out that his PSA has risen and therefore cancer is present. We’re unsure of exactly where - the PSMA scan (he’s unable to have a CT scan due to the hip prosthesis’s) didn’t show anything so we’re told the cancer cells are currently too small to be seen (good news in one way!) and that we now have to wait for them to grow. In the meantime, my Father In Law (this week) has been advised that he’s unable to have any sort of radiation as he has 2 metal hips and therefore his only option of treatment is hormone therapy. We’re hoping this isn’t the case and would love to hear of your experiences if it’s similar or if you have any help/advice. 

Thank you in advance!

User
Posted 21 Aug 2024 at 21:18
I have had a PSMA PET and a hip replacement, I was also told to have my hip replaced BEFORE any salvage therapy as the radiation can impede the hip healing.
User
Posted 21 Aug 2024 at 12:53

Hello,

I’m hoping for some advice/answers on behalf of my Father In Law as hours/days of researching online hasn’t come up with much. 

A brief history - after being diagnosed with prostate cancer he had a successful prostatectomy a couple of years ago but has now just found out that his PSA has risen and therefore cancer is present. We’re unsure of exactly where - the PSMA scan (he’s unable to have a CT scan due to the hip prosthesis’s) didn’t show anything so we’re told the cancer cells are currently too small to be seen (good news in one way!) and that we now have to wait for them to grow. In the meantime, my Father In Law (this week) has been advised that he’s unable to have any sort of radiation as he has 2 metal hips and therefore his only option of treatment is hormone therapy. We’re hoping this isn’t the case and would love to hear of your experiences if it’s similar or if you have any help/advice. 

Thank you in advance!

User
Posted 21 Aug 2024 at 17:44

You may not be aware that for radiotherapy, the beam is shot from many different directions, at the prostate. The reason for this is to reduce damage to surrounding tissue. 

The following is a very simplified explanation of a radiotherapy plan:

To delivery a full dose of RT to the prostate. 25% is fired from above, 25% from below, 25% from the left and 25% from the right.

This means that any part of the body only gets a quarter dose, except the prostate which gets hit by all four doses. 

The plan gets more complicated, because the radiotherapist wants to avoid hitting the rectum and some other organs, so the beam from below won't be fired directly from below it will be fired from slightly one side. Also no two paths should be exactly opposite each other, but I won't explain why. In reality they will use more than four paths, probably up to ten if they can.

As the hip prosthesis are probably made of metal they will block or scatter x-rays so the radiotherapy plan becomes much more difficult to design, as they have to avoid any x-rays hitting the hips.

Also the metal will make any scans of the prostate very blurred, so it will be harder to know where the target actually is.

I would not have thought this would make radiotherapy impossible, just more difficult, but I'm not a radiotherapists so how would I know.

I googled hip prosthesis radiotherapy, and this article came up.

https://humanhealth.iaea.org/HHW/MedicalPhysics/Radiotherapy/Topicsofspecialinterest/ManHipProsRT/index.html

I guess the fact I have a degree in physics might be the reason I found this easy to read and understand.

Dave

User
Posted 22 Aug 2024 at 10:53

Originally Posted by: Online Community Member
You may not be aware that for radiotherapy, the beam is shot from many different directions, at the prostate. The reason for this is to reduce damage to surrounding tissue. The following is a very simplified explanation of a radiotherapy plan: To delivery a full dose of RT to the prostate. 25% is fired from above, 25% from below, 25% from the left and 25% from the right. This means that any part of the body only gets a quarter dose, except the prostate which gets hit by all four doses.

This is a description of original IMRT (and it's not even correct for that which used 5 aiming points so the exit beams didn't lay directly on entry beams from another angle).

All external beam treatment today (in the UK at least, and probably for 5+ years) is IG-VMAT, which treats continuously while doing a 360 degree arc (excluding some SABR treatments). It's not possible to treat through a metallic hip because that reflects the X-rays to other places and some intended dose is lost from the prostate, but this is allowed for in the planning, by disabling the beam for the short time it would have hit the metal, and compensating throughout the rest of the treatment arc.

Proton beam treatment isn't possible with metallic hips, as proton beam only treats from two positions, and that's through each hip.

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User
Posted 21 Aug 2024 at 17:44

You may not be aware that for radiotherapy, the beam is shot from many different directions, at the prostate. The reason for this is to reduce damage to surrounding tissue. 

The following is a very simplified explanation of a radiotherapy plan:

To delivery a full dose of RT to the prostate. 25% is fired from above, 25% from below, 25% from the left and 25% from the right.

This means that any part of the body only gets a quarter dose, except the prostate which gets hit by all four doses. 

The plan gets more complicated, because the radiotherapist wants to avoid hitting the rectum and some other organs, so the beam from below won't be fired directly from below it will be fired from slightly one side. Also no two paths should be exactly opposite each other, but I won't explain why. In reality they will use more than four paths, probably up to ten if they can.

As the hip prosthesis are probably made of metal they will block or scatter x-rays so the radiotherapy plan becomes much more difficult to design, as they have to avoid any x-rays hitting the hips.

Also the metal will make any scans of the prostate very blurred, so it will be harder to know where the target actually is.

I would not have thought this would make radiotherapy impossible, just more difficult, but I'm not a radiotherapists so how would I know.

I googled hip prosthesis radiotherapy, and this article came up.

https://humanhealth.iaea.org/HHW/MedicalPhysics/Radiotherapy/Topicsofspecialinterest/ManHipProsRT/index.html

I guess the fact I have a degree in physics might be the reason I found this easy to read and understand.

Dave

User
Posted 21 Aug 2024 at 21:18
I have had a PSMA PET and a hip replacement, I was also told to have my hip replaced BEFORE any salvage therapy as the radiation can impede the hip healing.
User
Posted 22 Aug 2024 at 10:53

Originally Posted by: Online Community Member
You may not be aware that for radiotherapy, the beam is shot from many different directions, at the prostate. The reason for this is to reduce damage to surrounding tissue. The following is a very simplified explanation of a radiotherapy plan: To delivery a full dose of RT to the prostate. 25% is fired from above, 25% from below, 25% from the left and 25% from the right. This means that any part of the body only gets a quarter dose, except the prostate which gets hit by all four doses.

This is a description of original IMRT (and it's not even correct for that which used 5 aiming points so the exit beams didn't lay directly on entry beams from another angle).

All external beam treatment today (in the UK at least, and probably for 5+ years) is IG-VMAT, which treats continuously while doing a 360 degree arc (excluding some SABR treatments). It's not possible to treat through a metallic hip because that reflects the X-rays to other places and some intended dose is lost from the prostate, but this is allowed for in the planning, by disabling the beam for the short time it would have hit the metal, and compensating throughout the rest of the treatment arc.

Proton beam treatment isn't possible with metallic hips, as proton beam only treats from two positions, and that's through each hip.

 
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