PSMA scans and radiation of oligometastases

[Horse12888]

I need some advice on a subject that I know has been covered before: PSMA scans and radiation of oligometastases.

G4+5=9, RP in 2014. Positive margins, IMRT and ADT in 2015. PSA undetectable until 2019, now slowly rising at 0.40, doubling time 11 months.

My questions/concerns about the scan/radiation approach:

If I am going to go this route, what’s a good PSA level and/or doubling time to start?

Does it confer a benefit to overall survival? Some people say that whole approach is essentially “treating PSA,” meaning that you’re missing cancer types that don’t throw PSA, and that this is therefore worthless.

If I have a few macroscopic tumors, doesn’t this mean that I probably have hundreds that are, as yet, too small to be seen? If that’s the case, isn’t a cure under these circumstances is extremely unlikely? And given that, what's the imperative to get on this when my PSA is so low? Why not let it drift up to 5 or even 10, then get on intermittent ADT?

[Tall_Allen]

No one knows if it (metastasis-directed therapy -MDT) accomplishes anything. That doesn't mean it doesn't - it just means we don't have any convincing data yet. So my opinion is, if safe, why not? Where are the metastases?

But hormone therapy is known to slow progression. A recent trial showed that MDT+ADT can provide longer vacations if you opt for intermittent ADT. But why wait for metastases to spread and grow?

[Horse12888 in reply to Tall_Allen]

Thanks for this, TA. In your opinion, is 0.40 with a doubling time of 11 months a good time to jump in? What's your opinion of high-dose transdermal estradiol as an androgen suppressant?

[Tall_Allen in reply to Horse12888]

Where are the metastases?

[Horse12888 in reply to Tall_Allen]

I haven't had the scan yet; my inquiry here is to determine if I should get one, and, if so, when.

I'll also be interested to learn your opinion of high-dose transdermal estradiol as an androgen suppressant.

[Tall_Allen in reply to Horse12888]

How do you know whether there are oligomets?

Certainly, get a PSMA PET scan before even thinking about therapies.

[Horse12888 in reply to Tall_Allen]

Considering I haven't had the scan, I can't possibly know if there are zero, oligo, or hundreds of mets. I'm just trying to plan ahead. When's a good time to do a scan, given my PSA at 0.40 and PSADT of 11 months? Hoping you can add some insight there.

I'll also be interested to learn your opinion of high-dose transdermal estradiol as an androgen suppressant.

[Tall_Allen in reply to Horse12888]

Now would be a good time. Plan when you have more info.

[Horse12888 in reply to Tall_Allen]

Thanks. I think I'm going to roll with it.

[Break60 in reply to Horse12888]

I won’t comment on tx of oligomets. But I’ve been using estradiol patches since early 2019 with great results.

[Nusch in reply to Tall_Allen]

Hi TA, do you have more infos or even an link to the study you refer to?

[Tall_Allen in reply to Nusch]

On MDT? There are lots of studies reviewed in the section III here:

prostatecancer.news/2020/07...

[Nusch in reply to Tall_Allen]

Many thx TA - the best I’ve ever seen by now! I was wondering, if you also can provide a link for your statement: A recent trial showed that MDT+ADT can provide longer vacations if you opt for intermittent ADT.

[Tall_Allen in reply to Nusch]

The EXTEND trial is covered in section V9 here:

prostatecancer.news/2023/04...

I want to stress the conditional statement I made: "if you opt for intermittent ADT." I am not saying that intermittent ADT is a good idea even with iADT.

[Nusch in reply to Tall_Allen]

I misunderstood your statement and therefore wondered as I think to know your position regarding iADT. Thx for clarification, TA.

[Tall_Allen in reply to Nusch]

I don't think I have a position. It depends on how disagreeable ADT is.

[Nusch in reply to Tall_Allen]

I‘m lucky tolerating ADT very well.

[Nusch in reply to Tall_Allen]

Wow - you are doing so great! Good luck for your next 50 years.

[Justfor_]

Don't let it grow, it isn't a linear with time process, hence not fully reversible. Maintain a low PSA with a mild anti-androgen drug. Check my Bicalutamide maneuvers thread.

[Exrunner in reply to Justfor_]

What do you consider a low PSA?

[Justfor_ in reply to Exrunner]

For my case anything less than or equal to 0.050 is within my comfort zone. Ideally, I would like it to stabilize at 0.025-0.030 so that bilateral margins exist permitting dosage readjustment. For the latest two months, I am at 0.011 & 0.010 and hence planning to reduce dosage for getting PSA above 0.020.

[Exrunner in reply to Justfor_]

Those values from what my doctors have told and from my reading are non-detectable and you are in remission. A value over .1 is considered detectable and at .2 BCR if you had a prostatectomy.

Whatever you had done and are doing is working for you.

Good luck

[Justfor_ in reply to Exrunner]

Wrong in both. Silly or plain lazy docs use the term "undetectable" in a broadened context, that of: "I can do nothing for you" and at the same time keeping tha patient happy. First off, my lab's piece of kit has a "Limit of Detection" down to 0.003. Any value above that is surely detectable. Next, I wish I were in remission but I am NOT. I am in tight control of my BCR after prostatectomy 4+ years ago. I am sensitive to the miniscule quantity of Bicalutamide but if I were to stop taking it, or even drastically reducing it, my PSA would start climbing at a very fast rate. All of the previous have already been tested and documented. They are not theories to keep the patient happy.

[Exrunner in reply to Justfor_]

Interesting!

[Hidden]

Psma pets are relatively new at least in the USA. So much to be learned.

Personally speaking I would not be getting psma pets if i didnt intend to act on the information.

Act to me means radiation to the critters when safe in conjunction with other therapies as part of an overall strategy sure, but I am going to blast the critters to kingdom come as long as my dr’s say its safe.

Every met is a source of spread. Maybe, just maybe, the ones that are seen are the only ones. The odds are (way) against it, but the odds are not 0.

Even if it keeps things manageable for additional years its a win.

[dans_journey]

I went for a Ga-68 PSMA PET scan at UCLA in November 2021 when my PSA was 0.22 ng/mL, knowing that the chance the scan would pick something up at that PSA level was less than 50-50.

I was hoping to use the scan results to guide my salvage radiation as my PSA began accelerating in its increases. On the positive side, it didn't light up like a Christmas tree showing the spread anywhere/everywhere.

The chart in this post was from this paper:

pubmed.ncbi.nlm.nih.gov/309...

I went ahead with salvage radiation to the prostate bed alone with concurrent androgen deprivation therapy—a single 6-month dose of Eligard given 2 months before starting SRT. My PSA went from 0.36 ng/mL just before starting SRT to 0.11 ng/mL nine months after SRT ended. I go for another PSA test in early November to see if it continued to drop.

Good luck.

Chart showing percent positive PSMA PET scan results by PSA level.

[DennisDworak]

I’ve been fighting Prostate cancer for 28 years.. Been thru most treatments over the years and am on my 9 th Doc due to retirements & them moving. I had a PSMA scan last May when my PSA had risen to 3. It showed 2 hot lymph nodes nothing else. I had my RO kill those with SBRT. It seemed to have worked because my PSA has gone down to 0.01 and has stayed there.. My MO says I’m in remission.. YEAH ! It’s been a long 28 years so just stay the course and if I were you I would get that scan done somewhat soon. Good Luck.. p.s. I’m turning 80 in a couple of weeks.

[BruceSF in reply to DennisDworak]

Let’s hope it stays down after the radiation! Have you been on adt the whole time - or did you get it with the radiation?

[Horse12888 in reply to BruceSF]

I quit ADT at the end of 2015. Felt better by summer 2016.

[BigJ32 in reply to DennisDworak]

This is great to hear. I love the stories of long term remission. I’m new to the PC world, and telling you, I’m freaked out!! Stories like this give me hope that that a long life is possible (I just turned 56)

Thank you

[Horse12888 in reply to DennisDworak]

Yes, that's a great result. Thanks.

[DennisDworak]

Never went on Lupron. Had a lady Onco that insisted I go on it. I outright fired her.. Got an Orchiectomy instead. Same SE but no chemicals in my body. I’ve been on Zytiga and Prednisone for about 3 years now and my current Onco wants me to stay on those as I am tolerating them well and he says it will help prevent a reoccurrence.. But I sure miss my testosterone..Hope this helps.. Good Luck

[Horse12888 in reply to DennisDworak]

Intermittent ADT is not inferior to continuous. You'd need T replacement, of course.

[maley2711]

Might be of interest.....

youtube.com/watch?v=e5RLsgi...(Not working as expected?)

youtube.com/watch?v=v0DANKb...(Not working as expected?)

youtube.com/watch?v=wCbMNk9...(Not working as expected?)

youtube.com/watch?v=TW14J0w...(Not working as expected?)

youtube.com/watch?v=UlW9Q86...(Not working as expected?)

Also, TA has mucho info on your questions...check his blog.

Google and pubmed will also keep your busy, if you so choose!!!

we have more questions than there are answers!!!!???????

[Wife32]

This may be helpful for your decision.

Stereotactic Body Radiation Therapy and Abiraterone Acetate for Patients Affected by Oligometastatic Castrate-Resistant Prostate Cancer: A Randomized Phase II Trial (ARTO) RESULTS:

DOI: 10.1200/JCO.23.00985 Journal of Clinical Oncology - published online before print September 21, 2023

Best of luck.

[MateoBeach]

Get the PSMA scan now. Then go forward with some knowledge (even though incomplete) rather than speculating in the dark. If you have 4 or fewer targetable mets on the scan then treatment is worthwhile, even though 2/3 will have recurrence elsewhere within 2 years. Lu-PSMA (Pluvicto or others) may be an option or an add-on.

[Horse12888 in reply to MateoBeach]

Thanks very much.

[Exrunner]

You might want to look at urologytimes.com/view/exper...

[ron_bucher]

Two of my oncologists say they have seen many patients go into remission with that approach. When you have advanced cancer, remission is the first goal!

I got 5 years of remission from Taxotere plus prophylactic radiation of abdominal lymph nodes after my PSA began rising with clear scans.

[dmt1121]

I attended the Pacific NW Prostate Cancer Conference over the weekend. A Dr. Philip Cohen from Lions Gate Hospital British Columbia stated that a minimu m PSA of 0.4 - 0.5 is necessary to get any reliable results. Here is the chart he provided.

Detection Rates for PSMA PET-CT Scans

[Horse12888 in reply to dmt1121]

Thanks. Very helpful.

[dmt1121]

Glad I could help. I had been looking for this myself and was very pleased to see someone actually provide some guidance on this.

Good luck.

[Horse12888 in reply to dmt1121]

I just left my oncologist's office. She's advised me to wait another four months and see what the PSA is then. She also noted that my doubling time is 11 - 12 months, so she sees no urgency and comments, as you did, that it's unlikely to find some with PSA < 0.5.

[jackwfrench]

Similarly 2.5 years post RP I have right iliac/T10 PSMA and MRI lesion sitings but when they also saw spots in the lower left sacrum on the MRI, I could not get RO or MO to endorse me getting oligo rad to supplement systemic HT, and hopefully provide a vacation or 2. Now 2 months into HT my PSA is down from 2.2 peak to .1 but I still believe applying rad to problem areas cant do anything but help in the long term battle. I have found one RO that will do it, looking for a concurrence before I start. Other than hot flashes I am good, but time will wear me down with Lupron/Abi. Also trying to plot a path...