30 replies to this topic

[mabony]

apper - i meant PAPER

[Trey]

Regarding the 3 log (logarithmic) reduction issue, the progress in eliminating leukemic cells is measured this way.  So for example, if the "8%" your Onc told you about was your PCR number at diagnosis, then the log reductions would be as follows:

Baseline:                8.0%

1 log reduction:      .8%

2 log reduction:     .08%

3 log reduction:     .008%

Many labs are starting to normalize log reductions to their testing equipment, so can provide the log reduction as an average of their testing experience.  Ask your Onc to provide the log reduction number that your PCR represents.  Your next goal for an excellent response is the 3 log reduction, which is also called a Major Molecular Response (MMR).

[mabony]

Thank you very much, Trey.

[mabony]

n

[mabony]

Hello Trey,

I'm back again with the results.Finnaly. It' now 0.75%,after 6 month of G., at the begining it was 8%. The 3 log reduction as you explained to me, it should happen in 3 consecutive tests?

Hope i'm not a real pain in the...

[PhilB]

Hi Oona,

No, you don't need the three log reductions to happen one after another in consecutive tests.  The definitions generally used for optimal vs sub-optimal response are in terms of 2 log reduction (= CCR) by 12 months and 3 log by 18 months.  Some people are lucky eniough to get straight to a 3 log recuction in their first 3 months.  Others are still plodding along trying to reach it after 10 years or more - note that means that even though these 'turtles' haven't reached MMR yet they are still alive and well.  General thinking is that CCR, once you've held it for a couple of years, is just as good as MMR.

Best wishes

Phil

[gunner]

Phil pontificated- "I thought we'd already established who it was on here who couldn't divide / multiply (or indeed add or subtract)"

Reminds me of a story I heard many years ago....

And He told the animals to 'Go forth and multiple'. Some time later, He was confronted by a pair of snakes who said to him 'We are but simple Adders. How do you expect us to multiple?' He then went into the woods, cut down some trees, and made them a picnic table.

Because, as everyone knows:

With a log table, even adders can multiply!

[PhilB]

Now that will have everyone under 40 scratching their heads!

(And I thought my pontification fairly mild given the provocation!)

[mabony]

Hey Phill,

Thank you for your reply. How are you? I've come along your thread "a dose of my own medicine"..and I didnt quite understand. So you've had a 1 year PCR and the tests results were higher by 0.1%?(haven't practice my english "skills" in a very looong time)Are you on Glivec too?You know, since i've get my dx, i've been thinking as you said "i'm going to die", it's only a matter of time. We commemorate 1 year since my mother died (8 months since my dx) and i saw her evolution (brest cancer, it took 4 years until...). It's hard for me to think different. But i am still ok, and hopping for the better. As you said, in some cases it takes more time than in others, and you still are on medication, dont worry too much, you will be ok. I hope to hear good news from you,

[mabony]

Hi gunner

If I get your story right - good story, well chosen comparison, too bad it's about us..hmm?our case, our cells...

[gunner]

Phil is right. We are a couple of dinosaurs who many years ago used tables of logs of numbers for the purpose of dividing and multiplying. The slide rule is a physical device usine logarithmic marks so that numbers can be multiplied or divided. I used to have a book that had all of the calculated trig functions, a book of logarithmic numbers (Base10 and Natural Base), and I have used a book of random numbers. All made obsolete by simple calculators or functions on a spreadsheet.

The use of logarithmic scales makes sense when assessing how much change we are seeing in PCR levels. If you look at it from a linear perspective, you achieve remarkable change the first three months, and then the line is down in the tiny numbers category. When you see the numbers bobble around a little, it can be unsettling. Most of us have seen that. The log reduction puts these tiny bobbles into the correct perspective.

Some of us have worked with statistics, with different methods of plotting and assessing data, and with some of the fancier math. I am sure that it is confusing for many people, and I will try to help anyone with plotting numbers so that you can see them on a log plot.

Now, just a reminder for the technical types: Alcohol and Calculus don't mix. Never Drink and Derive.

-Norm