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Factors Influencing PCR Test Results?

Hi folks,

This is my first posting to the forum, so a little by the way of an introduction: I've been here on and off for the last four years since Dx.  After a poor response with Imatinib (PCR low of 5% and then starting to climb) I was changed to Dasatinib 2.5 years ago and reached CMR in six months, popping down to "undetectable" for a couple of quarterly tests about one year ago (that Dasatinib is good stuff!). 

Since that point my PCR tests have come back up fractionality and bounced around a little (0.007 last time), but this got me thinking about whether there is something to do with how and when I was taking my medication that might influence the result - something I could control rather than being in the lap of the gods!

As this forum is a relative mine of information, I thought it'd be worthwhile seeing what opinions you folks had on how the following might affect the results:

* What time of day you take your tablet(s)?

* One large dosage tablet, or several smaller ones?

* What time of day you have your test?

* Diet - foods avoided or taken, including alcohol?
* Exercise in general - better to keep fit or not be active?

* Exercise - immediately before sample taken (I had to run to the clinic one time as I was late!)

* Other medication

Your thoughts would be much appreciated.  I just had a look through my lab results and could almost see a correlation between the size of the control sample and the proportion of positive samples detected.  Can anyone explain specifically what the BCR-ABL and ABL Control columns are showing?

Thanks,

Glenn
 

Hello everyone

I was diagnosed with CML in January 2008 having just turned 50. What a present !

Fortunately the abnormality in my blood was detected  at a routine blood donor session.

Initially I had a short course of chemotherapy then I started my treatment with Glivec, after early problems with 400mg ( I had a break of a week or so) I resumed the treatment on 200mg a day, this dosage was very gradually eased up by my consultant, Dr. Stephen O'Brien over the following two years, he closely monitored my blood counts etc.  until i reached 400mg a day again.  

Now I still suffer from some side effects but not as severely as I did initially. ( at one stage I couldnt walk due to bone pain ).

I am posting this to encourage more recently diagnosed sufferers as I found out today that my pcr is now zero !....0.00000000 at last !

This site is excellent, there are many fellow cmlers who offer help and support when you need it most.

Glen....... I am sorry if my comment has tagged itself onto your posting I am rusty with the operation of this site !

In response to some of your questions I have always found taking my medication ( Glivec) with a very large glass of water after my evening meal suits me best. Or later in the evening so I am resting or asleep during the worst of any side effects. I try and keep active although sometimes the tiredness which can accompany this treatment makes this difficult.

In terms of diet I have been very lucky. I think moderation in all things is good advice. ( including alcohol )

best wishes

Bill Yellowley

Bill,

What have your PCR readings been like over the last 3 years?  has tehre been any fluctuations up or plateaus?

I am just asking because mine was going down swimmingly then jumped up a tad last time.  I was dx in Nov 2009 and have been on Gleevec 400mg for just over a year. Here is a list of my PCRs:

Late Nov 2009 - 68%

Mar 2010 - 1.4%

Jun 2010 - 0.8

Aug 2010 - 0.2% - BMB = 0 Leukemic cells CCR?

Nov 2010 - 0.43%

Have my next appointment early Feb and Onc was talking about possibly switching drugs if I plateau or go up for 2 PCRs so will see what he says... He wants MMR (3 log by 18 months so just need another0!)

So once again well done 

Ian 

 

Glenn, There is an earlier posting on the Forum that was a precis of a talk given to Kings College Hospital patients by the head of the lab that does  PCR tests for Kings patients.(18th October 2010). His view was that once result is below 0.01 the accuracy is not too good, which means some of your results could be due to random movements in result.

On the particular issues

1. I'm convinced after 4 years on Imatinib that its best to take tablet(s) with biggest meal of day in the middle of the meal. If I don't do this ( e.g. only take tablets with light meal) I get stomach problems. I then assume the drug might not be absorbed very well.

2. I take 600 mgs a day, all with main evening meal.

3.time of test is normally about 13hours after taking tablet. I think plasma levels of Imatininb peak a few hours after taking tablet and then tale off. I'm not certain about absorption of Dasatinib though? It's difficult to know if minor dips in plasma level would lead to a number of leukemic stem cells becoming active and leading to a higher PCR.

4. A fairly substantial meal seems to be the key  in my case. i.e. only a light salad and fruit for dessert seems problematic. I still have some alcohol and i know care is needed cos of potential liver problems. I try to make sure that i'm not having more than an average of 1 unit per day.

5 I think that exercise is great if you have no other underlying health problems, and side effects of mendiaction are not too bad. Don't overdo it though.

6. I try to avoid strenuous exercise for about 3 days before test? I have found no evidence about this. It was really based on those surveys about drug effectiveness where i've assumed perhaps wrongly that those in the surveys, would not have perhaps been engaging in aerobic exercise on a regular basis.

7. Other medication. There is quite a lot on the web about drub interactions and imatinib.

Not too certain on your last point but i would have thought that the bigger the sample, the more accurate it would be, especially at low levels of PCR.

Hope the above is helpful

Regards

Andy

Thanks for the link to the previous post - useful info.

When I was on Imatinib, if I didn't take the tablets with a meal it did make me feel sick, but Dasatinib doesn't have that effect, or come with any specific instructions on the time of day to take.  So...I'm debating whether to take in the evening or morning - is it better to be resting whilst it does its stuff, or better to be active?

I have no other significant side effects from the Dasatinib either, so taking exercise is no problem, more wondering whether getting your blood pumping around your system is a good or bad thing?

Others thoughts appreciated.

Glenn