Post-SRT/ADT PSA Monitoring

[dans_journey]

Greetings. I had a radical prostatectomy in 2011 that ultimately failed, with biochemical recurrence happening several years down the road. Last summer, I had androgen deprivation therapy (ADT) initiated two months before starting 35 sessions of salvage radiation therapy (SRT).

Here's the timeline:

30 NOV 2021 - PSMA PET/CT scan was inconclusive when my PSA was 0.23 ng/mL

18 APR 2022 - PSA 0.36 ng/mL

03 MAY 2022 - Received six-month dose of Eligard

07 JUL 2022 - Start SRT (70 Gy to prostate bed only over 35 treatments)

26 AUG 2022 - Ended SRT

13 SEP 2022 - PSA 0.05 ng/mL

01 NOV 2022 - PSA 0.05 ng/mL

07 MAR 2022 - PSA 0.13 ng/mL

The radiation oncologist (RO) said that it could be a minimum of 12 to 18 months before we see if the radiation did its job. The initial substantial decrease in my PSA was attributed pretty much exclusively to the ADT, but as the ADT dose wears off, would it be reasonable to expect the increase in my PSA before the SRT fully kicks in? Or am I just completely out to lunch and need to be more concerned than I am? (I have a follow-up with my RO in May.)

Thanks.

By way of background, my post-surgery info: G 3+4, negative margins, no SVI, no LNI, no extra capsular extension.

[Tall_Allen]

Did you receive whole pelvic SRT or just the prostate bed?

[dans_journey in reply to Tall_Allen]

Just the prostate bed.

[Tall_Allen in reply to dans_journey]

A PSA over your starting PSA (0.36) may indicate some untreated cancer in the pelvic LNs.

[Fred312 in reply to Tall_Allen]

What is the cut-off PSA for pelvic wide radiation vs prostate bed only?2.5y+ years out from RP, so far so good, but realize how quickly that can change. G 3+4. TU

[Tall_Allen in reply to Fred312]

0.35 - but it's not really a cut-off. Judgment is required.

[Justfor_]

The increase is due to the ADT wearing off IMO. PSMA PET/CT before the RT?

[dans_journey in reply to Justfor_]

Hi. Yes. I had a PSMA PET/CT scan on 30 NOV 2021 at UCLA when my PSA was 0.23 ng/mL. It was inconclusive. Nothing "lit up," so it couldn't guide the RO in his zapping plan.

[Justfor_ in reply to dans_journey]

That is good news. I have run across papers that gauge the sRT success from tops 65% to as low as 35%. Say on average a 50-50 deal. BUT, these numbers come from blind irradiations. There is a 10-20% (depending on pre sRT PSA) that can tell the sRT is destined to fail as there are positive detections outside the irradiation field. Consequently, a negative detection swings this 50-50 (a bit) in favour of success. My gut feeling is that your PSA will get a bit higher with time, but as long as it is within the 50% of the pre sRT one this is a good omen. If you are anxious to know sooner than later retest after one month. It will be more illuminating than 10 specialist's opinions at this point in time. Best of luck to you.

[tango65]

If your PSA continues to increase, when it gets around 0.4 or higher consider requesting a PSMA PET/CT.

If pelvic lymph nodes were present and there are not distant mets you could request irradiation of the rest of the pelvis plus a boost to the positive nodes. You could also discuss doing 2 years of ADT plus abiraterone.

[MateoBeach]

Get testosterone measured now to confirm recovery of testicular production is occurring. Therefore the rising PSA, especially if the next value is higher and not lower, indicates more cancer present somewhere. And most likely site, and most “curable” would be in pelvic lymph node fields. Would go back to RO to plan for SRT to pelvic fields. Not helpful to wait! You can get a repeat PSMA scan when PSA goes above 0.2 and perhaps get localization.

[RJAMSG]

Good evening Dan, I remember checking out your blog before and it helped me in my journey with some good information. You had what must have been over 4 years of undetectable PSA from 2011 to 2016. What happened from 2016 till 2022, just curious. Thanks Rob

[dans_journey in reply to RJAMSG]

Hi Rob,

Great memory! My post-surgery PSA was undetectable for 54 months after surgery and, in September 2015, it became detectable again at 0.05 ng/mL. In that fifteen months after it became detectable, it went up and down between 0.04 ng/mL to 0.08 ng/mL, not really giving us an obvious trend. But in November 2016, my PSA was 0.06 ng/mL and began a slow but steady climb.

It took nearly 6 years from my PSA first becoming detectable again until it hit the magical 0.2 ng/mL, the traditional definition of biochemical recurrence in June 2021. During those 6 years my medical team and I agreed to monitor closely without taking any action.

My two biggest concerns with salvage radiation therapy were the potential long-term side effects and zapping blindly, not knowing if we were aiming the radiation where the cancer was truly located. My line of reasoning was, "If we zap the prostate bed when the cancer had already escaped elsewhere, I'd be incurring the side effects with zero chance of the radiation being effective."

In July 2021, my PSA was 0.21 and I decided to pursue a PSMA PET/CT scan at UCLA to see if we could located the cancer before zapping. Unfortunately, it took about 2 months to have the VA, my insurance, and UCLA all get on the same page before I could get the scan scheduled (which I ended up paying $3,300 out of pocket after all of that). By the time all the details had been worked through, the earliest available appointment for the scan was 30 November 2021.

I went into the PSMA PET/CT scan with a PSA of 0.22 in October 2021 and I knew from my research that there was a less than 40% chance that PSMA PET/CT scans would detect anything when the PSA was less than 0.5 ng/mL. I went ahead with the scan and it didn't light up (good thing), but it also didn't provide the radiation oncologist with any useful information to plan his zapping.

On 5 January 2022 my PSA was 0.26 ng/mL which was a bit of a larger jump than we had been used to. I met with the RO in February 2022 to plan the zapping for starting around April. But in March, I was having some unrelated health issues that needed to be investigated pretty urgently, and that delayed the start of the SRT.

My PSA jumped again to 0.33 ng/mL on 11 March 2022 and then to 0.36 ng/mL on 18 April 2022. It was quite a rapid rise between January and April that surprised all of us given how slowly it was increasing over the previous 6+ years.

We agreed to do concurrent ADT with the SRT, and the RO wanted to have the ADT in my system for 2 months before beginning the zapping. On 3 May 2022 I received the 6-month Eligard dose, and we began 35 sessions of zapping on 7 July 2022.

We used the same lab throughout the PSA testing, so that gave us some consistency.

[RJAMSG]

Once again, I appreciate your exact detailed information. I’m also a patient at the VA and work for the VA in IT infrastructure. It can take some time to get through the bureaucracy. Some of the data has changed a little since you started your treatment with early and very early salvage RT, I was told to not wait long to start zapping if it returns and then there is RY to the prostate bed only, prostate and lymph nodes and all that and hormones. What was your % of 3 and 4 on your final pathology report, we have similar numbers and Age at start of treatment. I waited a little longer to start because my PSA bounced up/down below 4 and then VA stopped PSA testing for a couple of years too. I am following your case closely, prayers for decrease on PSA!

[CAMPSOUPS]

You're a scholar and a gentleman.

[j-o-h-n]

Yes they do now.... but they weren't very friendly to me in 2012. And me being a USO Commando..........

(Beware the ides of march).

Good Luck, Good Health and Good Humor.

j-o-h-n Wednesday 03/15/2023 1:50 PM DST