Stalled PSA decline after SRT

[Mike1600]

Hi All, following a PSA of 4.2 and biopsy I was diagnosed as Gleason 3+4 T2cN0 (0/15) R0. I had an RP in Dec 2018 and was undetectable for 18 months before PSA slowly began to climb. In 2024 my PSA hit 0.2 and I had a PSMA that identified a small tumour by a clip from surgery in the prostate bed.

May/June 2024 was given 33 sessions 71.6Gy to tumour, 66Gy to prostate bed, excluded lymph glands, and no ADT. PSA immediately before Salvage Radiotherapy was .22 then 3 months after SRT (Aug 5th) PSA had dropped to 0.1 which was promising. A second PSA taken Oct 28th, 6 months after SRT, shows I have stalled at 0.1

I am assuming this is my post SRT nadir so have requested an appointment with my radio oncologist in the UK to discuss the results and implications although I realise it is still early days.

I can’t find much on time to nadir for SRT rather than for RT as the primary treatment. Is there a typical time to nadir for SRT and like RT can there be a PSA bounce.

On the assumption that 0.1 is my nadir, would reoccurrence be considered when and if my PSA reaches 0.3

Lastly when I see my RO are there any further questions you would recommend I ask.

Many thanks for any input

[Justfor_]

Was the PSA report 0.1 or 0,10 (great difference)?

[Mike1600 in reply to Justfor_]

Hi, Justfor. It is 0.1

[Justfor_ in reply to Mike1600]

Then it can be anything from 0.05 to 0.14.

[Mike1600 in reply to Justfor_]

Ahh sorry the comma threw me it's 0.10

[Tall_Allen]

Radiation can take a long time to reduce PSA.

[Mike1600]

Thanks for the info TA

[MarkS]

Hi Mike, I see you're from Southampton, I'm just down the road near Havant! Are your PSA tests on the NHS or private? The NHS test tends to have an accuracy of only one decimal place, whereas the private tests I have are sensitive to 3 dp. My PSA test through the local surgery was <0.1 on 30th May this year whereas my test through BUPA was <o.oo6 on 29th Aug.

[Mike1600 in reply to MarkS]

Whoops - managed to reply to myself. So reposting - Hi Mark, yes not so far away I am being tested via my NHS local surgery the results back just stated 0.10 without any < sign beforehand. Something to query with the Oncologist who I will be paying to see as I think the NHS fogot to follow up with me. All the best - Mike

[Leaffan57]

that’s awesome that it has worked so far… has the same until my PSA hit ..24 a year after the SRT… now it’s ADT, Erleada and radiation to the spots on my rib and hip. PSA now undetectable.

[Mike1600 in reply to Leaffan57]

Thanks for sharing your experience Leaffan57. I'm preparing myself for the next stage of this journey. Great news that you are undetectable.

[Pford62]

I have similar situation , slight uptick on my last test .0.11 to 0.14 , could this be Nadir as well. Doctor didn’t even comment on it in MyChart so i guess it’s nothing to worry about

[Mike1600 in reply to Pford62]

Thats a big drop from a PSA of 31 (in you bio) down to 0.11/0.14 Guess that leaves us both in the watch and wait position. Hope you PSA remains low for a long time.

[Mgtd]

I am in that “watch and see” mode also. It can be somewhat frustrating but I prefer that to going back on ADT immediately. You have to weigh taking action prematurely versus waiting to long. So far I am comfortable with the “watch and see” approach and so is my MO.

At our next visit in Jan 2025, if the PSA continues very slowly rise my goal is to eastablish some real criteria for further action. In the interim life goes on.

I guess it comes down to the individual and your oncologist comfort zone in dealing with a reoccurrence.

[Mike1600 in reply to Mgtd]

I like your approach of watch and see so as to make informed choices. Plus as you say life goes on. That's my preference too.

[NanoMRI]

Seven years ago I had the same salvage RT regime, done at 0.11. My three month nadir was 0.075 and we accepted cancer remained - that it had already spread beyond the prostate bed. IMO no reason to give it more time to carry-on. Post RP I rely on uPSA <0.010 as best indicator and do not think in terms of recurrence - but rather - that cancer remains. Suggested questions: what PSA to rely on to indicate cancer remains; how long should you wait (three months was correct for me); how often to test not give this best time (I test bi-monthly - well ahead of guidelines). After my unsuccessful salvage RT I chose salvage extended pelvic lymph node dissection surgery, done at 0.13, instead of ADT. All the best!

[Mike1600 in reply to NanoMRI]

Thanks NanoMRI those are some useful questions to ask. Appreciate your insights.