Lutetium treatment timeframe

[topofthemountain]

We know that LU-177 is not a cure but can reduce the PSA by killing tumours that exhibit PSAM. We all so know that PSA tends to rise after LU-177 treatment ends. So why are Lu-177 treatments given every 8 weeks. If LU-177 has reduced the level of PSA why not give the treatments every six months after PSA has risen again?

[Tall_Allen]

Maybe because of re-population.

[topofthemountain in reply to Tall_Allen]

Thanks Allen.

[AlanMeyer]

Pure speculation - to be ignored if someone actually knows the real answer.

I speculate that Tall_Allen is right. They're trying to really smack down the cancer, not knock it part way down, let the weakened cells recover and repopulate all the tumor sites before doing it again - each time facing a fully recovered, more resistant, less PSMA avid, tumor population.

On the other side, they probably wait 6-8 weeks to avoid overdosing the patient and making him sick (or dead). The half life of the isotope is 6.7 days, so it takes 6-8 weeks to get the dosage down inside the patient so it's safe to treat him again. For some patients it may still be worthwhile to treat him again later when the PSA gets high again.

[topofthemountain in reply to AlanMeyer]

Thanks Allen

[zengirl in reply to AlanMeyer]

Alan- My husband is getting the Lu-177. How safe is he to be around him after that. He feels like he should go to an Airnbnb for a week to be safe around the family, What are your thoughts on this?

[noirhole in reply to zengirl]

Dependent on your dosage I would get treatment on Thursday and could not sleep with my spouse until Saturday. Remember you should also not have your dogs on your lap for the same period.

[zengirl in reply to noirhole]

Thank you for letting me know. They used to keep these patients in the hospital but no more.

[AlanMeyer in reply to zengirl]

I don't really know the particle physics involved in Lutetium-177 radioactive decay. I just now looked them up on the Internet, looking at an article on Lu-177 in the Wikipedia and an article on Lutetium-177 handling precautions here: perkinelmer.com/CMSResource...

I shall now, while pretending to be a particle physicist, produce a ridiculously inexpert prediction about the dangers.

If I understand what I read, the primary radiation from Lu-177 decay is beta radiation, which is composed of electrons and positrons (positively charged electrons). I suspect the positrons are all absorbed very quickly inside the patient.

The handling precautions say that the maximum distance for beta particles in air is 53 inches. If so that would mean that you and others would be completely safe in the same room with your husband as long as you all stayed 4-1/2 feet away. Think of it as social distancing.

However that's a maximum distance in air. The beta particles first have to go through the mass of your husband's body which, I am guessing, will absorb the great bulk of the radiation before it gets out to the air. The maximum range of the particles in water (which is most of what we are) is only 1.6 centimeters (as per the handling precautions), less than one inch. So I think it's likely that the amount of radiation that makes it to the air is a relatively small part of the total radiation.

Another consideration is the question of how long you need to take precautions. The half-life of Lu-177 is 6.71 days. That means that at the end of 6.71 days only half as much radiation is given off. At the end of another 6.71 days, half of the half is given off, or 1/4. Another 6.71 days and it's down to half of the half of the half, or 1/8, and so on. At the end of a bit over two months, it's down to 1/1024, less than one thousandth of the initial dose. That's getting to be a pretty low dose.

Now, having said all that, my advice is to completely ignore my blathering and ask the radiation oncologist. Ask him how close you and others can get to your husband, for how much time (for example, giving him a quick kiss is way less exposure than sitting right next to him on a sofa while watching a two hour movie, and for how many days is it desirable to take precautions.

Any rad onc worth his salt should have researched all these questions. If he hadn't, he shouldn't be offering Lu-177 treatment to anyone.

Best of luck.

Alan

[zengirl in reply to AlanMeyer]

You are the best. Thank you.

[Teddysdad]

I agree with what Tall Alan and Alan Meyer have written.

I am about to have my 8th Lutetium Treatment at the end of the month. I had 6 over a course of a year which knocked the PSA down from 1,585 to 88 over the course of about a year.

Doses where very much given depending on my health, this year my PSA has started to rise again, currently 220, and so I am having 2 more doses to knock it back down.

A point to note is that i had no side effects for the first 6 treatments but when I had the 7th back in February it really wiped me out and while no specific reason has been given I put it down to radiation sickness, so in some ways I am becoming less tolerent of the treatment.

They are talking about the possibility of me going up to 10 treatments but we shall see what happens!

[topofthemountain in reply to Teddysdad]

Thanks Teddysdad. Your first 6 treatments achieved a great result. I agree with the two Allens that the cancer does re-populate. However what I am trying to get my head around is that if the treatments are further apart would we end up with the same result.

[tennis4life]

Where are you being treated? I'm searching for less costly.

[topofthemountain in reply to tennis4life]

I am being treated in Brisbane Australia. I have had two treatments to date. After my first treatment my cancer PSA reduced from 50 to 3.5. I had my second treatment on 8 April 2021. I get the results in May after blood test and body scans.

[topofthemountain in reply to tennis4life]

I forgot to mention that the cost is $10,000 per Lu-177 treatment.

[Mckelz in reply to topofthemountain]

Did you have this treatment after all others failed/ completed AD, chemo etc or can you opt to go for this first in Australia?

[topofthemountain in reply to Mckelz]

I was treated for LU-177 after Enzalutamide failed. I have never had chemo. To receive Lu-177 in Australia you must have at least one AD failure. I had robotic sugery in ealy 2018 and became metastatic in 2019 and received Eligard until PSA started to rise, moved to enzalutamide which failed in late 2020. I am an earlier adopter of LU-177 it is a good treatment with minimal side effects. It is expensive at $10,000 a treatment but does extends life.

Doctors are giving 6 infusions of LU-177 at 8 week intervals.But the end of the treatment PSA will rise again as it is not a cure. I am keen to understand the implications of extending the timeframe between each treatment. If the PSA rises again after an interval of say 12-16 weeks between each treatment, the question is whether the next treatment of Lu-177 will reduce the PSA again. A roller coaster approach. It appears that Doctors want to get the PSA down during the treatment eventhough they know it will arise again after all LU-177 treatment ceases.

[Mckelz in reply to topofthemountain]

Thanks for all the info much appreciated, we are over the ditch in nz and I think we have to wait until all options have failed including chemo. Dad has just become castrate resistant so next step will be chemo or arbitrone. Had read that studies are happening on the effectiveness of LU-177, prior to chemo for those with small number of metastasis but I don’t think we can just “choose” to try it first and instead wait until the diesase has spread further.

[marnieg46 in reply to topofthemountain]

Wasn't there a trial suitable for you being run at Peter Mac?

[topofthemountain in reply to marnieg46]

There were earlier trials but no trials when I decided to have LU 177.

[marnieg46 in reply to topofthemountain]

Oh! That's a shame. None now?

[tennis4life in reply to topofthemountain]

Thanks TOP!

[TeleGuy]

I was treated at TUM in Munich and their preference was to do it every six weeks. They said that they found that the cancer started recovering when they used an eight-week cycle. Once my PSA was down to nothing we switched to an eight-week schedule.

[Ybor]

It may reflect the degree of disease burden. I have had two treatments in Heidelberg, Germany, about two years apart. In both instances, my PSA had risen from non- detectable to around 4.0. In the first instance my PSA declined steadily over the period of two years to non-detectable. I just received my second treatment in fall of 2020 and the PSA has declined to 0.2.I realize I am rather unique in obtaining Lu-177 treatment with a relatively low PSA, but I chose it over Chemo in consultation with my Doctors at Mayo.

Thus far, I have had virtually no side effects and the treatments have been relatively successful.

[topofthemountain in reply to Ybor]

Hi Ybor. Great results and I think early treatment with Lu-177 is the way to go. I have had two treatments with LU-177. My first treatment reduced my PSA from 50 to 3.5. I will not have my results for the second treatment until May. I agree Doctor's treatments are based on disease burden and re-population. My preferences are for early treatment which I am undertaking and increased periods between treatments to extent life on this treatment. Your story for me is so valuable for discussions with my Doctor.

[chips1942]

It is probably premature to suggest that Lu 177 treatments may not be curative for earlier stages of PCa. Most all the trials which have been conducted so far were on men who were castrate resistant. Hopefully, men who have less advanced prostate cancer will be qualified for clinical trials in the future and we will see exactly where Lu 177 fits into treatment protocols.

[Bangkok]

I had three treatments in Bangkok last year where their protocol is only one month apart. My PSA dropped from 9.98 to 0.10 but after 8 months it was doubling again. I came back in January and had one more treatment. I am now doing 20 treatments of IMRT concentrating on the prostate. Last year the Lute-177 treatments removed a multitude of bone mets. I was lit up like a Christmas tree and my spine looked like I needed structural repair. This year there is not a met to be seen and my spine has completely regenerated. My opinion at this stage is the radio ligand treatments can only do so much but to get down and dirty in the prostate you need "Focal" radiation. I'll keep you guys informed - we are all learning. By the way it seems the vessel is important in the outcomes. I have run 16 marathons in my career and at 74 I still run 5 K a day and do a lot of cycling. I have never - not once, felt like I have cancer. That is the injustice of this disease..

[Kbeez]

Does anyone know if this is available in the UK?

[Poowater]

I'm on my second infusion. I will not get another until psa rises.

[Poowater]

Seems logical when buying time. What are your Mets?