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To Ultrasensetive PSA or standard PSA that is the question

User
Posted 11 Apr 2019 at 00:03

Ok has it really been 1 year since my last PSA (ultrasensitive) ?  I guess the appointment card gave the game away. 

The question on my mind was do I "do a Bollinge" and go for a standard PSA? Hopefully I will get a less than 0.1 and I could be happy for another 12 months. Or do I stay true to form and go for USPSA? And perhaps have to worry about 0.0 whatever? 

I have pretty much decided I would need it to be over 0.1 before pushing the button on SRT so it's a valid question.

Well I know what I chose - what would you guys and gals have chosen?

Either way I still have the 2 week wait to find out!

User
Posted 11 Apr 2019 at 03:39
I have no choice other than to have a ‘standard’ PSA as the billion pound super-hospital my sample goes to only test to 0.1, and my GP says he has no way of paying for a test elsewhere where they do super-sensitive testing.

I did have a test at the Royal Marsden, who only test to 0.04, which came back as <0.04. Someone here suggested there should be standardisation of these tests across the NHS - an excellent idea.

Cheers, John.

User
Posted 11 Apr 2019 at 04:47

I’m convinced of the merits of the ultra sensitive test.  Post RP, my PSA was 0.014.  It crept up to 0.023 over the space of 12 months.  My oncologist was suspicious that cancer remained despite the low readings.  I had a PSMA scan and cancer was found.  I’ve since been treated with SRT and HT.  Now, imagine I had been in a hospital which didn’t do the ultra sensitive test.  I might still be <0.1 undetectable.  I’d therefore be untreated and the cancer would be growing and possibly spreading.

 

i therefore think more men could benefit from ultra sensitive testing.  But my personal example can’t be applied to all men.  I was pT3b, Gleason 9, positive margins.  All factors were taken into consideration in my case.

 

 

 

User
Posted 11 Apr 2019 at 08:22
I am not sure that John would ever have made a decision to move away from usPSA - the decision was made for us by the local NHS pathology dept deciding to change to 1dp and the realisation that we were paying the local private hospital a small fortune to process the PSA via the NHS!

Tough to make the decision yourself

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

User
Posted 11 Apr 2019 at 09:46
Strange isn't it here in Wales the NHS will only do 1 decimal place so I could get tested locally to 0.1 that would save me a trip to England to have it done privately.

In England the private hospital sends the samples to Wolverhampton NHS because the private path lab changed their policy and won't/can't do USPSA!!

User
Posted 11 Apr 2019 at 10:19

Imagine the discussion.

'We need a new psa analyser and one measuring to 0.1 is £20,000 cheaper, takes less time plus less patients will be asking for retests and extra tests.  The downside is some patients will fall through the net.'

Manager,  'How many fall through. Very few. The savings sound good let's go for that'

Although 0.1 could be more logical if they're not going to treat you until it's higher, except for the like of Ulsterman.  Also we know Lyn's husband has been stable at 0.09.

Probably low level testing is better in the early days after surgery until they establish a trend.  Then more coarse testing could be used.  Although 0.05 sounds about right for most, to reduce spurious results as well. 

I think I'd be more worried at this time with a <0.1 result, whereas <0.05 is still quite low if it does rise and I could judge the trend.

Finally I think I'd pay for ultra sensitive for 3 years at least.

 

 

 

 

 

Edited by member 11 Apr 2019 at 10:23  | Reason: Not specified

User
Posted 11 Apr 2019 at 10:35
I had a number of 0.05 (< never mentioned) readings before RP relapse. What makes me mad is that so many people seem to have had early intervention (<0.1) but I had to wait until over 2.0. That plus anything over 0.0 1 or 0.02 post SRT seems destined for relapse if you read stories here and elsewhere. I feel my lot were either too conservative, too budget bound or weren’t bothered. It may just be my sour grapes mind you.
User
Posted 11 Apr 2019 at 13:21

You’re all worrying me now... not really. I’m happy with my four <0.1 and one <0.0.4 post-operative readings and am due for another one this month. Except my mate has just invited me to his penthouse in Geneva, so it will have to wait till May.

Gypsy Petulengro’s readings for me are quite auspicious anyway, as I am G4+3=7. I realise others are not in the same boat and not so fortunate.

Yes, I did ask my GP if I could have super-sensitive assay PSA tests in nearby Wolverhampton, and he said no. It seems the ‘National’ Health Service is really a local health service in some cases, as evidenced by the PET-PSMA scanner at the Royal Marsden, only available to local people.

Cheers, John.

Edited by member 11 Apr 2019 at 13:25  | Reason: Not specified

User
Posted 11 Apr 2019 at 14:08

Ignore me. I’m just feeling pissed off because this damn disease (cancer not specifically PCa) is going to take a dear friend over the next few days.

Edited by member 11 Apr 2019 at 14:09  | Reason: Not specified

User
Posted 11 Apr 2019 at 15:30

I only have the PSA test to one decimal place.

I had a reading of <0.1 1st June 2016, the next reading was 0.3 on 1st September 2016.

My PSA quickly rose to 0.7 by end October or so.

I can’t help feeling that if I had been tested on the ultra sensitive test a rising pattern would have been picked up earlier like with Ulsterman.

That has haunted me somewhat but would it have made any difference?

I don’t truly know bu5 I would have the usPSA if given the choice.....

Ido4

User
Posted 11 Apr 2019 at 17:10
I think a lot of places ignore movement below 0.1 even when it has time after time been a marker for relapse
User
Posted 11 Apr 2019 at 17:25

"We need a new psa analyser and one measuring to 0.1 is £20,000 cheaper, takes less time plus less patients will be asking for retests and extra tests. The downside is some patients will fall through the net."

I think the equipment is standard; managers or clinical services decide what level to report to. When Leeds changed from 3dp to 1dp they already had the equipment but the findings of a large scale research project concluded that 2 or 3 decimal places is unreliable.

Edited by member 11 Apr 2019 at 17:26  | Reason: Not specified

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

User
Posted 11 Apr 2019 at 18:12
As ever, so many “What if’s” with PCa, as in life generally.....

Cheers, John.

User
Posted 12 Apr 2019 at 07:39
Lynn

So your saying 0.05, 0.01, 0.02 etc. are all within the same error range?

User
Posted 12 Apr 2019 at 07:46
Pete I seem to recall Lynn saying their oncologist said 0.01-0.05 could all be the same reading

Bri

User
Posted 12 Apr 2019 at 08:31
Ok cheers

I just hope my 0.7 gets to that point

User
Posted 12 Apr 2019 at 13:05
Pete, do you sometimes get your decimal places in the wrong place? I don't think you have posted about your PSA rising to 0.7 ... did you mean 0.07? And earlier in the discussion you said that your doctors made you wait until 2.0 but I think they waited until you reached 0.2 which is the official threshold for biochemical recurrence.

The debate about statistical tolerance applies to any test result, not just PSA of 0.01 - 0.05. The mathematical / scientific basis is that for any given result the tolerance could be, let's say for argument's sake 0.04 so a result of 0.07 could in reality be anywhere from 0.05 to 0.09 Add in the 3rd decimal place and a result of 0.070 could be anywhere from 0.045 to 0.094

Once you get over 0.1 the tolerance range becomes less significant so a result of 0.16 could be anything from 0.14 to 0.18 which is going to make no difference to a doctor's assessment of whether there is a recurrence.

As far as PSA testing goes, I am only basing this on what Mr P and Mr B have told me about why locally they have stopped offering usPSA. However, the time that dad gave one blood sample that was then tested twice on the same day, he had two results ... 0.30 and 0.32 :-/

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

User
Posted 12 Apr 2019 at 13:25
Lynn

I meant 0.07 post srt and action was stated to be over 0.2 for post to and over 1.0 for post srt. It’s been a long week in a new job so my brain is fried.i think my niggle is that I had to wait for a rise to 0.24 whereas lots of people here had their oncologist jump on post rp relapse well below 0.24 which I understand increases success rates. It made me feel the post rp threshold should be lower say 0.15.

Either way I just need to wait and see

User
Posted 12 Apr 2019 at 13:46
I think the issue in your case was that the test sequence was 0.05 / 0.05 / 0.05 / 0.16 - the 0.24 was only a month later so there wasn't a delay as such, it just rose rapidly once it decided to rise.

If the threshold was 0.15, it would have made no difference to your timeline. Your rise from 0.05 to to 0.16 was in the February, the surgeon would have referred you to oncology and probably would have retested your PSA in March to rule out infection.

You had a raw deal in getting cancer and then BCR - hopefully, there is some peace of mind in knowing that you did not experience delays compared to others and accepting that the doctors responded appropriately to the data available - it was just that the data changed very quickly?

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

User
Posted 12 Apr 2019 at 13:52
Yea you are right

I reviewed ages ago and it was actually nearer 10 weeks between the 0.16 and 0.24 as they delayed the oncology review and I booked the test just before it.

So bad but not as bad as it could have been. Still fast DT but MSK give me 95%/80%/70% survival for 5/10/15 years with my stats very roughly as some figures were a guess.

Just gotta let the dice roll.

User
Posted 12 Apr 2019 at 14:26

This is a popular subject yet I don't think any of us know much about it.  It would be good if a guest biomedical scientist would provide a write up.

I read a piece about how they do the test and it seems they machine is calibrated using a standard sample then it does its jiggerypokery.  I'd be sure there will be a few manufacturers and they probably have different specifications as I once saw an advert for a machine that claimed to be more sensitive than others.

Also I'd feel the tolerance of accuracy would be no more than 10%, which on a 0.05 reading would be +/- 0.005.  If it was +-0.02 it wouldn't be that useful even at 0.1.

I once read that 0.03 is a threshold above which errors are insignificant.   Although they do say to get tested at the same place as there are differences in the calibration.

We are talking about 0.03 nano grammes per millilitre.  1 nano being a billionth of a gramme in a thousandth of a litre which is a millionth.  Amazing!

Yes, If you prefer there are 2 Gypsy Petulengro's and you could see if there's a difference in their predictions.  The daughter on the pier and the mother on the pleasure beach.

User
Posted 12 Apr 2019 at 15:43

Is PSA 100 percent consistent in our blood stream and would it be 100 percent consistent in the split blood sample Lyn's Dad provided ? 

Thanks Chris

User
Posted 12 Apr 2019 at 16:25
I did speak to the actual biochemist in the pathology department at our ‘billion-pound’ super-hospital who carries out the PSA testing, and I asked her about super-sensitive assay and why they only give results to 0.1, i.e. <0.1, ‘undetectable’.

She was most helpful, and foolishly said:’If you need any more information, please come back to me’.

So I will be back in touch to find out more. She may live to regret it........

Will let you know make and model of the instrument, calibration schedules, etc., etc.

I don’t contribute here just out of benevolence, self-preservation is also involved....

Which Gypsy Petulengro is the most accurate, and when was she last calibrated?

Cheers, John.

User
Posted 12 Apr 2019 at 22:28

Originally Posted by: Online Community Member

Is PSA 100 percent consistent in our blood stream and would it be 100 percent consistent in the split blood sample Lyn's Dad provided ? 

Thanks Chris

 

My professor of pathology friend told me that it would depend which bit of the sample you were looking at on the slide. 

 

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

User
Posted 12 Apr 2019 at 22:37
Something something blind man at the dartboard
User
Posted 12 Apr 2019 at 23:36

In reply to Chris about whether the blood in one arm will have the same level of psa as in the other. I'd say yes because blood is pumped around the body many times and likely to equalise.  Although there are probably better reasons.   If a sample was split and put into the same analysis it would also be the same as the machine pumps the blood many times through a sensor, or so it appears.  To find the bit in a million probably takes a few swills.

To John as gypsy forecasts are pretty random I'd go to the daughter but it's a matter of taste and PCness.  Looking forward to the self preserving non benevolence.

Edited by member 12 Apr 2019 at 23:37  | Reason: Not specified

User
Posted 12 Apr 2019 at 23:40

Originally Posted by: Online Community Member

If a sample was split and put into the same analysis it would also be the same as the machine pumps the blood many times through a sensor, or so it appears.  To find the bit in a million probably takes a few swills.

 

In Dad's case, one sample was split and tested twice = two different results. 

In John's case, sample given at 8.30am and another at 9am (in different places but both tested at the same lab) = two different results

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

User
Posted 12 Apr 2019 at 23:43
I have Tarot cards and the I Ching if that helps....
User
Posted 15 Apr 2019 at 18:07

Maybe I can shed some light on what can be expected from an analytical method and a PSA measurement.

There are two parameters that characterise any method used to measure the amount of any chemical in blood be it a natural component e.g. PSA or an administered drug e.g. aspirin. When the analytical method is being validated the biochemist determines the accuracy and the precision of the method. The accuracy is a measure of how close the measured value in a blood sample is to the true value (which can never be known - only estimated). The precision is the scatter of values obtained when exactly the same sample is measured a number of times. It is highly likely that if the same blood sample is analysed 10 times then 10 different values will be obtained. The aim of the biochemist developing the method is to minimise these variables. 

Usually validated analytical methods will will be accurate to within e.g. 5% of the true value. Likewise the measured value will be expected to fall within a range expressed as plus or minus e.g. 5%.

So when we get a PSA value reported as 10 ng/ml the true value will lie somewhere between 9.0 ng/ml and 11 ng/ml. 

I would encourage all not to get hung up on small differences in PSA values.

My last three values were 2.7 ng/ml (april 2018) 2.5 (august 2018) 2.8 ng/ml (january 2019). As far as I am concerned these values are essentially the same and the differences are a reflection of the random errors inevitable in any analytical measurement.

User
Posted 15 Apr 2019 at 19:54

 

 

There must be millions of stored blood samples in the US.  In the case below the manufacturer only supplied calibration down to 0.1 whether that was the limit in 2004 or if it was a cheaper machine I don't know.  The machine does the calculations.

Here's an extract from a Lab Procedure dated 2004 along with the link to the full manual:

 

 

The instrument automatically calculates all results. After testing is completed, results are printed and review by the technologist. Samples with results > 150 ng/mL are diluted off-line and repeated; results are corrected for the dilution factor. Samples with results < 0.1 ng/mL are repeated to confirm. 

Results are reported to the nearest tenth (0.1). The lowest reportable PSA result is 0.1 ng/mL. The assay does not have a maximum reportable limit since off-line dilutions can be made to bring the concentration within the working range of the assay. Estimates of imprecision can be generated from long-term quality control pool results.

The upper reportable value is virtually unlimited. The upper limit for undiluted specimens is determined by the calibration material supplied by the manufacturer. Values exceeding this upper limit are repeated on dilution until values, prior to correction for dilution, fall between approximately 5.0–150.0 ng/mL B. The lowest reportable value is approximately 0.1 ng/mL. The lower limit of this assay’s default dilution is determined by the calibration material supplied by the manufacturer. Values below this lower limit are repeated to confirm the result.

The residual serum is stored at ≤ –70o C for 6 months after analysis, then it is returned to the NHANES Repository in Rockville, MD for long-term storage.

https://www.cdc.gov/nchs/data/nhanes/nhanes_03_04/l11psa_c_met_total_psa.pdf

 

 
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