Change in PSA testing method

[SoonerMark]

Previous testing was centaur chemilumisometric immunoassay with PSA of 0.31.

Fifteen weeks later, the new method is ECLIA with PSA of 0.63.

I'm been tracking the failure of RP and IMRT with rising PSA and plan to independently schedule PSMA in Europe. My UO has me waiting, doing nothing. What does the new method tell me ? Is my PSA increasing at a high rate ? Its doubling every 12 -15 weeks. At what point should there be treatment ? I feel my PSA is rising quickly and I want to be proactive, not passive.

I've asked for PSA's every three months and results have been 0.01, 0.05, 0.11, 0.21, 0.31 and finally the 0.63 with the new method.

[Justfor_]

I am alternating two labs at monthly rate and up to now I have found a max offset between them to be contained within +/- 20%. It is in accordance with the specs of each method as the intra-lab accuracy of each is specified at 20%.

Your rise from 0.31 to 0.63 exceeds this 20+20=40% so, it can't be attributed to different measurement equipment, assay, calibration, etc.

Regarding the "official" PSA value indicative of a second recurrence, I have seen the 0.2 (same as for 1st recurrence) but also 0.4, probably coming from a 0.2+0.2=0.4 combination.

The SoC book in your case says to wait for another fat, round, "magic" number (1 or even 2) and then start ADT.

Your decision to seek a PSMA PET/CT at this stage finds me in 100% agreement. There are things to be done in case the origination of recurrence is spotted, though you will hear the word "experimental" from SoC fans.

Go ahead and get good results.

PS.

I run your numbers as taken from your profile, under the assumption that all labA tests were dated the 15th day of the respective month. In particular, the latest labA = 0.31 on 15_Feb_21 and your recent labB = 0.63 on 31_May_21.

Extrapolating your labA regression (log regression coefficient R= 0.9905) the estimated log PSA rise came up to 0.33, meaning a 0.31+0.33=0.64, which is in perfect agreement with the labB results.

[SoonerMark in reply to Justfor_]

Thank you for the response. My magic number appears to be 1.0 but the only treatment this will trigger seems to be an auximum scan.

[Justfor_ in reply to SoonerMark]

I bet that PSMA PET/CT at 0.63 PSA is more sensitive than Axumin at 1.0.

Your docs are obviously bounded by what they have available and/or reimbursed by insurance.

urologytimes.com/view/evalu...

[Tall_Allen]

With that kind of PSADT, you should start on ADT.

[SoonerMark in reply to Tall_Allen]

Despite the PSADT, there hasn't been any discussion of treatment or strategy going forward. I've just been told to wait until my PSA is over 1.0. Is there a a school of thought there is a benefit to delaying the start of ADT or is earlier always better ?

[Tall_Allen in reply to SoonerMark]

There are 3 situations where most MOs agree that hormone therapy should begin in recurrent men:

• metastases or symptoms detected

• high PSA

• rapid PSADT

The TOAD trial suggests that there may be an advantage in starting sooner (before metastases are detected) but the trial was too small and only ran for 5 years, not nearly long enough to reliably detect differences in survival:

thelancet.com/journals/lano...

Most of the attention has focussed on hormone intensification (early use of second-line hormonal agents) before metastases are detected.

[cesces]

I would be doing the test month to month.

Get a test using the old assay right away. If it confirms the trajectory you should start treatment right away.

You don't have time to wait three quarters to recalibrate on your new test.

[SoonerMark in reply to cesces]

My last appointment was in February and I was told to wait until August for my next PSA despite the rapid PSADT. I called and asked to have another PSA at the beginning of June because I thought 6 months was too long. A nurse called and told me the results and said when my PSA gets over 1.0 they would schedule an auximum scan. There was no other information and my appointment wasn't moved up, its still in August. I'm not questioning the validity of the test, but wondering why there isn't something being done. From everything I've read, it seems that my doctor is taking a somewhat passive approach.

[cesces in reply to SoonerMark]

You don't want to take the auximum test until you get to 1.0.

Getting extra PSA tests can do no harm, can they.

You don't need the auximum test to make a decision to treat though.

There are far more accurate tests than auximum. But auximum is the one that for sure insurance will pay for.

Time to start traveling and getting some second opinions. Right away! Without delay!

[cesces in reply to SoonerMark]

Actually, in order to avoid a false negative, you want to wait until a PSA of 2.0.

But all the scan is going to do is tell you the location of the cancer. You don't need that information to begin treatment.

[Cooolone]

Your PSA is rising quickly and passivity won't help anything, at least in the form of testing. By the time you can get you test I would imagine your PSA to be in the 1.0 (+/-) range, making it a good candidate for a PSMA-PET scan for sure! Don't get too caught up in the methodology, unless of course the numbers are skewed badly. One reason that ultra sensitive PSA testing is a problem that too many people get mesmerized in the .00# range where it really doesn't make a difference.

Anyways, best regards!

[SoonerMark in reply to Cooolone]

Having the PSMA was my idea, but its not available in my area. I'm leaning towards a European location over UCLA or UCSF.

I feel fine but can't help wonder whats happening inside of my at the microscopic level. My personality is to get things done, to be proactive and solve problems. I'm certainly not well versed in medicine, but it feels like procrastination.

[Lasered]

I had a PSMA scan at UCLA in March when my PSA was .75 and it identified a tumor on a lymph node. I waited three weeks for an appointment. Cost was covered 100% by my insurance.