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3 log reduction confusion

Hi Just a quick post, had my routine 3 monthly visit to the hammersmith yesterday and got some great news (well i thought it was) that my PCR was 0.1. Excellent I thought MMR 3 log reduction super duper.

Then the Dr said actually for 3 log reduction and the target is 0.07 which got my slightly confused. But I was happy with getting down to 0.1 so didn't ask the question I thought about on the train ride ont he way home...

Is a 3 log reduction always 0.1 but only if you start from 100, and in reality if you where only say 70% at DX a 3 log reduction would be for that person 0.07? I had always assumed I was 100% ph+ at dx but maybe not

any thoughts?

Rob

Rob, I've had the same experience! After various up and downs in my PCR readings and an increase to 600mgs of Glivec, I at last reached 0.108 (nearly 3 log reduction, or so i thought ). However on visiting Kings in December, Dr Ho advised me that Kings assumed starting point is 70% so a 3 log reduction is 0.07. I think Kings take an average for their lab as the 70 % figure. I recall reading somewhere that really where you start in terms of the PCR reading is not too significant and in fact in one research paper the group in the study who had higher starting readings actually fell to a lower level after 3 months rather than the group with lower starting readings .

I guess the key thing to hold onto is that 0.1 is a good place to be and I'm sure that given more time you should drop to lower level Andy

Hello Rob,

I asked Prof Apperley [the Prof at Hammersmith] about the numbers for the magic 3 log reduction at the CMLsupport conference in London last November. She confirmed that the target is 0.07 at Hammersmith.

With regard to the 100% PH+ at diagnosis, yes you probably were, I think most of us were very close to that figure. But I'm not sure that you can directly correlate that 100% PH+ to a starting point of 100% for a PCR reading....other more scientific brains than mine will be able to explain it far better than I am able to! :-) I do know that the PCR figure can be higher than 100% at diagnosis if there are additional chromosomal abnormalities present.

I'm still chasing 3 log as well - latest figure in early December gave me a 2.6 log reduction. And as Andy rightly says, it is a good place to be, and fingers crossed over time we will all gently drop to lower levels.

By the way - you're not alone in thinking of questions to ask when you're on the way home. My brain never seems to function very well when I'm sat talking to my consultant, and despite taking in a notebook with all my questions written down I find it takes a bit to absorb all he says and make sense of it all...thank goodness for sites like this one and others like it, when questions can be asked at any time!

Hope that helps - or at least that I haven't added too much to the confusion!

Regards, Janet

Hi
My wife would be knowing her PCR soon. I read with interest all of your
postings on "log reduction" . Could someone please explain ?

Just to add to the above, what I meant to ask is 2, 3, n 4 log reduction.
How do you read them. Thanks
daniel

Hi Daniel
Depends on where you start, Hammersmith are assuming a Ph+ve level of 70%+ve, i.e.70.00
so if you move the decimal point to the left once, hence one log, move it two spaces, hence two log - 0.07 and 0.007. Does that make sense ?
I was told that I was at 100% for about 10 years, so surely my starting point should be 100.00, my last PCR was 0.18, so theoretically that should be a three log reduction ?
Sunday afternoon mathematics !!!!!!
Have fun and keep smiling
Keith

Hi Keith
Thanks for clarification as never too good into maths. Keeping my fingers crossed as will be visiting the heamatologist later this month.
daniel