Rising PSA after RP + SRT

User

Posted 12 Jul 2023 at 22:54

Hi All,

I got diagnosed with PCa in early 2020. with GS 7 (3+4) PSA 7.5 Had bone scan which showed no spread. Was put on Biculatamide due to lockdown to 'freeze' the cancer until August 2021 which reduced PSA to about 3 afyer when I then had da Vinci RP to take out prostate. Very little side effects from op which I recovered from pretty well. Some significant ED but function is slowly returning. PSA post-op was 0.07 and histology report confirmed intial GS 7 (3+4), N0, M0, T2c with clear surgical margins. It the started to rise over about about a year to 0.866 (it actually dropped at one point).

Then had a choline PET scan which was clear followed by SRT fractionated 66 Gys on prostate bed using conformal VMAT for 6 weeks which over 12 months reduced PSA down to 0.06 (nadir). Since then, I have had a slow PSA rise where 15 months on, it has climbed to 0.33. This is making me feel rather twitchy.

So I am not sure what is going on here. Clearly there were cells left over on the prostate bed which the radiation destroyed but maybe the radiation did not get it all, or missed some? Can some cells survive 66 Gy of 10 MeV radiation? Some cells may have gone AWOL elsewhere, but the scans and histology did not seem to indicate this. So am I heading for a Biochemical Recurrence (BCR)?

I know PSA can 'bounce' after RT but this is normally seen after RT to the prostate and is rare after SRT when the prostate has been removed. Also the definition of a BCR after RP is PSA> 0.2 whereas after SRT it is defined as 2.0 + nadir which is threshold 10 times more. Why is this?

I am 66 and want to live a good few more years yet.

Not sure what to make of it all...

User

Posted 13 Jul 2023 at 00:35

Sorry to see this Starman. It seems you are already in biochemical recurrence - it may be that you have micro-mets. Micromets often don't show up on scans because they are tiny and in a number of different places. The post-op pathology would not have been able to identify if you already had mets. Time now to have a conversation with the oncologist about next steps ... another scan, with a more sensitive tracer (PSMA or Axumin)? Restart hormone treatment? If so, at what PSA level would s/he recommend?

BCR post RP is 0.2 because there is no prostate - so only tiny amounts of PSA are produced in other parts of the body

BCR post RT is 2 + nadir because the man still has a prostate which will generate healthy PSA

BCR post RP + salvage RT is 0.2 because there is no prostate

Edited by member 13 Jul 2023 at 00:38 | Reason: Not specified

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

User

Posted 13 Jul 2023 at 22:57

Hi, Your 2 nadirs were 0.07 and 0.06. The peak was 0.86 followed by the most recent 0.33.

Was your RT directed at the prostate bed or a wider range. In any case it got 90% of what was there and you were left with 0.06 psa.

That level of psa wouldn't be detected by any scans although if it was in one place there is a low level chance it might be detected by a PSMA scan. Less likely by a standard PET scan. They usually say a PSMA scan might find something around 0.2 but they also say it's better to wait until 0.5 which gives about a 50% chance. Personally I'd want it before then as results are better below 0.5 and there's always a lag to treatment and it's still going up.

A PSMA scan sounds your best bet. There is a chance it's in a single area perhaps in a lymph node and can be treated with more RT. As Lyn says some questions and a PSMA scan sound the best bet. It might be hard work but keep on and push for that PSMA scan. All the best, Peter

User

Posted 13 Jul 2023 at 23:42

Hi Peter. Thanks for responding. I am not sure, but I think that the RT was directed at the prostate bed and may not have covered the outer areas. I had conformal VMAT from a state of the art Elekta linear accelerator which tightly focuses the beam in a confined area to avoid damage to bladder and surrounding tissues. The side effects I had from RT were mainly heavy fatigue from which I have largely recovered. A follow up colonoscopy showed evidence of scarring in my intestine where the beam went through but side effects on my bowel dynamics have been relatively mild compared to others peoples I have read. I also have had little in the way of incontinence as well. I generally feel OK.

I suspect you might be right that it didn't get 100% of it and some might be outside the radiation field nearby and was missed. From studies I have read, a PSMA scan can detect cells with 80% accuracy at PSAs above 0.2 There is always the chance of false positives though.

Trying to get an appointment with onco at the moment to see the way forward. I would prefer to have a PSMA scan ASAP to give a better diagnostic picture and see if there is a localized clump that can be destroyed with SRBT before going down the ADT route.

User

Posted 14 Jul 2023 at 08:07

Starman, I was in a similar position but with different time scales, RP 2014 ,SRT without HT,in 2017.

Following recurrence after SRT I had a PSMA scan at a PSA of 1.4 in May 22 followed by SABR in August 2022 ,to a pelvic lymph node the scan had detected. Pre treatment PSA was 1.8 and stay at that for only a few months before shooting up.

A PSA of 4.6 in April 2023 prompted another PSMA scan and detected a tumor in another lymph node and residue still in the first tumor.

PSA prior to another five SABR treatments was 6.1. 5th June 2023, I started five SABR sessions and six months of 150 mg of bicalutamide. More waiting to see if has been successful,but it is what it is. Next PSA test in a few weeks,but probably not too relevant due to the effect of the bicalutamide.

My first PSMA scan used the F18 1007 tracer and the second scan used the Gallium 68 tracer.

Thanks Chris

User

Posted 14 Jul 2023 at 11:04

Hi Chris,
Thanks for letting me know. Keep us posted.

User

Posted 14 Jul 2023 at 11:31

It does seem to me that RT can be quite literally a hit and miss affair in its ability to be 100% effective in targeting everything, whereas HT seems more systemic in the way it stops cell growth. Someone I know had a recurrence after RP and SRT after a scan showed a spot his spine. Following apalutimide, it is now almost undetectable and has stayed that way. Everyone responds differently I guess.

Edited by member 14 Jul 2023 at 11:40 | Reason: Not specified

User

Posted 14 Jul 2023 at 12:32

Starman,PSMA scans were not as commonly used back in 2017, based on advice from this forum I asked for a PSMA before SRT ,but it was refused. My onco said SRT to the bed it was a very educated guess based on years experience and data. Your first recurrence was alot quicker than mine and apparently that does make a difference to the approach to treatment.

I will let the scholars explain the HT .

Thanks Chris

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