17 replies to this topic

[jmoorhou]

Just wondering if anyone has experienced this, and how long does it take to get to a point where you have to increase dosage.

[gerry]

When is your next test?
Your current result is still in the noise levels. 200 may not be enough to keep showing PCRU, but you won't know until you can see whether it is a trend upwards or a blip.
Some of our TFR members continue to blip but their PCR doesn't rise any further.

[jmoorhou]

Gerry, thanks, I hope to god you are right.  I will get my next test any day, it is hard to believe it will not continue upward.  After four months of having my life back, I 'm not happy about going to 300 mg which the Onc said I could do, it hasn't been too bad.

[Trey]

If the .0007 is a percentage that would be more than 5 logs.  Most labs would just report "undetected".  This is when I say "calm the frickola down".

Edited by Trey, 30 June 2017 - 07:41 PM.

[jmoorhou]

Ok thanks Trey  would you mind  what are "logs"....did this happen to you?

[scuba]

10 raised to the power 0 = 1

10 raised to the power 1 = 10

10 raised to the power 2 = 100 (also known as 10 'squared')

10 raised to the power 3 = 1000 

 

.... see what is happening above.... just adding a zero to the result for each power raise. yields ... 1, 10, 100, 1000

The power number (0,1,2,3) are typically shown as 10^0 .... 10^1 ...10^2 , etc.  The number 0,1,2 are referred to as exponents.

 

Logs are just a convenient way to express powers of 10 (actually, any power, but power of 10 for CML purposes).in natural systems where the range of a variable is very large ... 

 

As an example in CML ....

 

going from 100.0% to 10.00% PCR is a one log reduction. The exponent went from "2" to "1" ... in order to go from 100 to 10. Note how the decimal place moved over one to the left.

 

going from 100.0% to 1.0% is a two log reduction ...

going from 100% to 0.1% is a three log reduction ...

going from 100% to 0.01% is a four log reduction ...

going from 100% to 0.001% is a five log reduction  ...

going from 100% to 0.0001% is a six log reduction ...

 

Your meaningless result of 0.0007% is between a five and six log reduction, hence Trey's response to you. (100% is the typical starting point in CML PCR reporting).

 

The number 0.0007% is meaningless because the precision of the PCR test as commonly done falls dramatically below about 0.01%.  False positives increase below this level and the accuracy of the test result is low at this level.  Many labs do not report values below 0.01% for this resaon. They either report <0.01% or "undetected". You may or may not have a detection of the bcr-abl protein (which is CML). For practical purposes, 0.0007% is the same as PCRU or "undetected". It's a meaningless number.

 

Your level would have to rise above 0.1% before loss of response should be considered.

 

Other forms of logs:

 

 

 

And yes, Trey was almost certainly hit by a log. That is what happened to him.

[jmoorhou]

Love the graphics Scuba, thanks for the info. 

[dchicago]

I am having similar experience.  I have been undetected for 2-3 years.  After some negotiation, finally reduced Gleevec to 300mg from 400mg.  The latest PCR after 3 months of dosage reduction is 0.0002% IS (i.e. MR5.5).  Dr said either re-test soon or move back to 400mg.  I'm waiting couple weeks to re-test.

 

If the .0007 is a percentage that would be more than 5 logs.  Most labs would just report "undetected".  This is when I say "calm the frickola down".

 

What is a frickola?  Is it a Pokemon?  What do you feed it to calm it down?

[jmoorhou]

.0002 is not bad. Does your Doc think it is. I talked to a specialist in CML, and he said 300 mg is ok.

Frickola is when you post on this site that you'd rather use the death with dignity law instead of staying on full dose.

[Pin]

Good lord, MR5.5 I would love to be at that level... Also, your lab must have good equipment!!

[dchicago]

.0002 is not bad. Does your Doc think it is. I talked to a specialist in CML, and he said 300 mg is ok.

 

Since I was undetected for a while, we started talking about cessation down the road.  Despite 0.0002% is a very low level, in my Dr.'s mind, it's no longer PCRU and 300mg may not be enough to keep CML at bay.  It resets the clock for cessation and so forth.

 

We haven't discussed the possibility of false positive in PCR test.  I'm not sure if they have better equipment for the test, or they just choose to report it certain way.  I am not yet convinced 300mg is not working for me.  So, I will wait for another PCR test.

 

How does false positivity in PCR come about anyway?  I thought they amplify the DNA and then count the BCR-ABL.  If there are no BCR-ABL in the sample to begin with, where could it be introduced?  Contamination from other samples?
 

[scuba]

Usually it is due

 

Since I was undetected for a while, we started talking about cessation down the road.  Despite 0.0002% is a very low level, in my Dr.'s mind, it's no longer PCRU and 300mg may not be enough to keep CML at bay.  It resets the clock for cessation and so forth.

 

We haven't discussed the possibility of false positive in PCR test.  I'm not sure if they have better equipment for the test, or they just choose to report it certain way.  I am not yet convinced 300mg is not working for me.  So, I will wait for another PCR test.

 

How does false positivity in PCR come about anyway?  I thought they amplify the DNA and then count the BCR-ABL.  If there are no BCR-ABL in the sample to begin with, where could it be introduced?  Contamination from other samples?
 

 

 

False positives are usually caused by contamination or mis-interpretation:

 

http://www.nature.co...l/2401899a.html

[jmoorhou]

I went from .0007 to .0009 after last four months at 200 - 300 mg....

[scuba]

I went from .0007 to .0009 after last four months at 200 - 300 mg....

 

Janis - think of it this way .... You went from 0.00 to 0.00 during the last four months. .... or, if you prefer, you went from 0.000 to 0.000 during the last four months.

 

The third and fourth decimal place is absolutely meaningless in PCR testing. There is no qt-PCR test that has precision and accuracy below 0.00 with the notable exception of digital PCR, which you are not using and don't need to use. Cessation is in your future when you feel comfortable giving it a try. That means zero Gleevec.

[jmoorhou]

I see that you are right Scuba, that wasn't a log change.

[gerry]

dchicago,
We have TFRers who continually blip at these levels and still remain off. It is always the trend that should be looked at

[jmoorhou]

Scuba,do you mean it might stabilize at log two.....

[scuba]

Scuba,do you mean it might stabilize at log two.....

 

No ... log two doesn't mean anything in your case. You have a PCR level in the noise of the test. The different levels from test to test mean nothing. You are indistinguishable from someone who is "undetected".