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FISH and PCR Tracking Questions


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#1 LivingWellWithCML

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Posted 22 July 2011 - 03:30 PM

Hi everyone,

I just received my 3-month FISH and PCR results today and have a few questions.  Any feedback you all have would be greatly appreciated.  I'm on Gleevec 400mg:

** PB FISH = 5% at 3 months (was 98% BM FISH at dx and 41.5% PB FISH at 6 weeks)

  • Although not CCyR at 3 months, it's close.  Despite what the guidelines say, is this fast enough to consider Gleevec the optimal TKI for now?  I think it is, but I just need some reassurance based on others' experience with treatment and speed of response.

** PB RQ-PCR :: BCR-ABL1 to G6PDH Ratio = 1.53E-02

  • What's the number that I should put into my PCR spreadsheet?  1.53?  Is this good/bad/indifferent at 3 months?  BM PCR at dx was 2.5E-01 (25.0).
  • The report defines baseline as the following: "Baseline represents the average BCR-ABL1/G6PDH ratio for a patient with CML, chronic phase, who has not received therapy."  Have others seen their PCR "baseline" defined in this fashion, and where does this average come from?  Is this a form of international standardization?  Confusion reigns.
  • Given the definition of baseline above, here are the result details in the report.  Is this how others are measuring the march toward MMR and (hopefully) CMR?
    • 19.13% of baseline
    • -0.72 log change from baseline

Thanks for your help in understanding this stuff, folks -

Dan



Dan - Atlanta, GA

CML CP Diagnosed March 2011

Gleevec 400mg


#2 Happycat

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Posted 22 July 2011 - 04:41 PM

Can't help with your questions, but I must say I am green with envy at all the FISH and PCR tests you guys get!  I don't get one until 6 mo.  I have no data I can graph yet!

Traci



#3 Susan61

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Posted 22 July 2011 - 04:55 PM

Hi Traci: I cannot help with any of this either.  I have never graphed anything with regard to my numbers.  I just look to be in normal range, and check everything else that is on the blood work to be sure its where it should be.  I just had my PCR test this past Monday, and I will get my results next Tues. when I see the doctor.  I think I would drive myself crazy if I tryed to keep track of every little number, but thats just me.  A lot of people like to keep track of everything, and keep a record of what is going on.  I wish I could keep records like that for future reference.  I just keep a folder with copies of all my testing.

There is so much that I cannot participate with in these discussions, but I admire all those who can do it.

Susan 61



#4 LivingWellWithCML

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Posted 24 July 2011 - 12:58 PM

No worries - I just want to make sure I understand this stuff and have some knowledge in my back pocket for my next appointment.

Thoughts anyone?


Dan - Atlanta, GA

CML CP Diagnosed March 2011

Gleevec 400mg


#5 Trey

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Posted 24 July 2011 - 03:16 PM

Tried to post earlier but random website errors have surfaced again.

FISH is good -- focus on that.

PCR:

-- Lab standard at diagnosis (developed by averages obtained at diagnosis for this lab)

-- Your PCRs do not appear to be International Standard, or they would have a correction value to calculate the IS result

-- Your "19.13% of baseline" is confusing -- does this actually mean that your initial PCR result of 25% is above the 19.13% baseline PCR at diagnosis for this lab?  If so, the -.72 log does not correlate to the 1.53E-02 (15.5%).  Does the wording say "19.13% of baseline" exactly?

Usually CCyR will be roughly a 2 log reduction from diagnosis.

Artificial average lab PCR baselines are not helpful in this regard.



#6 LivingWellWithCML

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Posted 24 July 2011 - 04:48 PM

I know - I'm finding this very confusing indeed.  I asked about all of this at my appointment (I saw the specialist's PA because he was on hospital duty), and the PA couldn't answer my questions.  I could tell that she was wondering why I even need to ask these questions?!  I appreciate you trying to help me make sense of it.

The wording on the 3-month peripheral blood PCR is verbatim: "Ratio: 1.53E-02.  Result Details: 19.13% of baseline, -0.72 log change from baseline".  I assume that their version of 'baseline' ratio is the artificial average that is stated in the report, and not from my PCR ratio at diagnosis.  Does anyone else measure log reduction in this way?

The marrow PCR that was run at diagnosis at the end of March says the following verbatim: "Sample type: Bone marrow.  Ratio: 2.5E-01. Log Change from Baseline: 0.50.  Percent: 312.50%".  It does not explain what 'baseline' is, so I haven't a clue what the log change and percent figures are or how they were calculated.  Confusion continues to reign.

I'm just trying to figure out what my baseline PCR ratio should be, so I can measure x-log reductions.  Should it be 0.25 (or 25), or .0153 (1.53)?  Not sure why they've made this so difficult to figure out ... ugh ...


Dan - Atlanta, GA

CML CP Diagnosed March 2011

Gleevec 400mg


#7 Trey

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Posted 24 July 2011 - 06:01 PM

Well, that is a bit more clear.  Your PCR at diagnosis was +.5 log (so your first PCR was half a log higher than the standardized lab baseline for that particular lab).  And your second PCR was -.72 log from the Baseline (NOT from your last PCR).  So you dropped the .5 log and another .72 log, so the combined drop was well over 1 log from your initial actual PCR result (ask someone else to calculate the actual log drop -- Phil will just make fun of me if I get it wrong, since he is the Exchequer to the Keeper of the Queens Royal Maths & Semi-Solid Waste Treatment Department, or something like that).  Anyway, I would care more about individual log reductions than comparisons to the average log reductions of all patients.  The reason is that you don't know when the "averaged" first PCRs was done in relation to diagnosis, and whether the patient had already started TKI drug therapy, or taken hydroxyurea, etc.

So you can either start with 19.13% and calculate log reductions, or start with 25% and calculate your personal log reductions.  I believe that if a person knows their personal diagnostic PCR, they should use that.  But it is all fuzzy math anyway, the key is whether you sustain an overall downward PCR trend (although not necessarily continuous downward PCRs on each test).



#8 LivingWellWithCML

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Posted 25 July 2011 - 12:37 PM

Ok, this does seem to help explain things a bit - I believe that dx and 3-month tests were all from the same lab at Emory, so I imagine that the baseline is the same for both.  I'm still not sure why they choose to measure against an arbitrary "average" baseline and not against a personal baseline.  To your point, I just want to see more zeros appear to the right of the decimal point as quickly as possible!


Dan - Atlanta, GA

CML CP Diagnosed March 2011

Gleevec 400mg





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