Free psa test

[Peterd110]

My doctor order a psa free test along with my regular psa test this time Wonder why???

[pjoshea13]

I would not have a biopsy solely on the basis of PSA. There are now other tests that can add PCa specificity, but when I was diagnosed there was only the free-PSA.

"The risk of cancer increases if the free to total ratio is less than 25%." [1]

-Patrick

[1] en.wikipedia.org/wiki/Prost...

[Peterd110 in reply to pjoshea13]

Well I already know I have stage 4 pca. Maybe it was just a mistake.

[pjoshea13 in reply to Peterd110]

Peter,

It does seem to be a mistake - but check with the doctor. -Patrick

[Tall_Allen]

Free PSA is not validated for any purpose beyond initial detection. You are well beyond that.

[kapakahi in reply to Tall_Allen]

I was wondering about that. I have had PCa since 2008, hopefully still contained within the capsule (according to the latest scans). I just had another PSA and free PSA - the PSA dropped from 2.0 to 1.5, the free PSA was 8%. I've always read that free PSA should be measured only if the PSA is above 4.0, but then I thought I've read here or somewhere else that it's valuable even when PSA is as low as 2.0, which I guess is why I got it, and also the chance that maybe I didn't actually have PCa anymore. But I've always assumed that I will always have PCa, even if it's slow-growing non-aggressive - the original Gleason score was 3+4 but that was 10 years ago. So I don't know if that free PSA score has any meaning and whether I should have a biopsy. The issue arose because after a few years when PSA hovered below 1.0, it went from 0.9 last November to 1.8 in April, then 2.27 in May, and my doctor said the cancer had probably started growing again and suggested a biopsy, which I haven't had yet. But then it went down to 1.8 in June, 1.5 in August, and back up to 2.0 in September. Now it's 1.5 again. I don't want yet another biopsy if I don't really need one, but this bouncing around PSA is very confusing.

And is there any substantive difference between a regular PSA test and an ultra-sensitive beyond the number of decimal points?

[Tall_Allen in reply to kapakahi]

There is another test that I would recommend to you called the Prostate Health Index (PHI). But, to my knowledge, both tests are only valid for PSAs in the 4-10 range. However, an analysis from Johns Hopkins suggested that % free PSA is still sufficiently accurate in the 2-4 ng/ml PSA range:

ncbi.nlm.nih.gov/pubmed/121...

4Kscore was validated for PSA>3. I don't know of any PSA-based tests that are valid for PSA<2. However, there are a few less-well validated non-PSA based blood or urine tests that may be worth checking out: Select MDx, ExoDx Prostate Intelliscore, or Apifiny.

As you say, ultrasensitive PSA only gives additional decimal points and is inappropriate for untreated men.

[Hidden in reply to Tall_Allen]

One of the things I learned from my research medical oncologist is the fPSA is part of a complete diagnosis. Measuring unbound prostate specific antigen in the vascular system is part of understanding total PSA in the bloodstream. With over a hundred blood tests under my belt, I always have Total PSA and Free PSA. Frankly, it is just another biomarker providing information to the specialist.

This topic leads to another: the role of the U.S. Preventive Services Task Force (you know the group which does not include PCa specislists) recommendations and a total lack of screening resulting in men with highly aggressive tumors missing their opportunity for a cure. To wit: the increasing number of men with their first diagnosis as metastatic cancer,

GD

[Tall_Allen in reply to Hidden]

What do you do differently because the fPSA is high or low? A test has no value unless it can potentially result in a change in treatment. Since PSA in a radically treated man comes from his residual cancer and no other source, what is the value of fPSA at that point? There are no known treatments for advanced PC that depend upon the results of fPSA. "Understanding" by itself is not a valid reason to have a test.