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Big Variance In PCR Results In Short Timespan

Anyone else ever see anything like this before…..

 

Diagnosed in 2015. Basically up until about 12 months ago my PCR has always been around .02-.04 for 2.5 years on 50mg of Sprycel on many tests from multiple labs (hospital/labcorp/mda). Then out of the blue 12 months ago I start getting some random higher results sprinkled between my typical ..03-.04s I get some .07s and .08s same results at both the hospital and labcorp. Then following these atypical high results now twice I have received a negative result from labcorp once today and once 7 months ago. The last negative was then followed by a .08 just 4 weeks later from the exact same labcorp lab! That would be a 1.4 log jump! Then a typical .04 from both labcorp and the hospital 3 months later. Followed by another negative result today from labcorp without getting results lower than .03 at either the hospital or at labcorp for the last 18 months! Makes absolutely no sense to me. I’m convinced the PCR Covid testing has screwed the accuracy of the machines in someway.

Going from .02 to .08 is ”just” 4x change, thats not even 1 log. I often got choppy results like that. 

What i noticed is that 50mg is simply not enough for everyone. I have read dozens of threads claiming that dasatinib gets more efficient with smaller doses, and i am familiar with the 50 vs 100mg trial literature, but my personal experience is very different.

I went into ND after ~2 yrs treatment with 100mg and I was able to keep ND for another 2 years on 50mg, however due to some side effects i had to pause my treatment (forced TFR experiment), lost the ND and 50 mg was not able to control my cml for several months, but finally ended up switching to 70mg and that did the trick. I have seen a lot of choppy results during the first 2 years of treatment, and after my failed TFR until i increased the dose.

I understand the anxiety what these results can create. Maybe try to look deeper into your habits, your drug compliance, and have a discussion with your dr about your dose. 

Best wishes!

—Thomas

 

 

Another thing worth mentioning: i did notice some changes in the pcr testing ever since covid. Test results out way slower, not sure how that affects the sample quality, and also the number of blood cells are consistently lower on the report card than before the covid times. In my samples there are normally 150-200k cell samples, but after covid i think they use less blood and the sample size is often below 100k, which can end up hitting sensitivity limits. Depends on the lab, but worth checking with a nurse or someone who knows whats what. 

Hi Thomas thanks for your response I guess what I find the most confusing are the two undetectable results I received in the last 12 months alongside the new also higher results like the .08s. The first one I received I thought for sure lab error but now that I have received two I don’t know what to think. I can’t imagine it really went from <.0035 to .08 in 4 weeks as it did the last time I got a negative result would be a nearly 25x fold increase. Then a .04 now I’m suddenly back to undetectable agai without ever seeing some results in the DMR range. I’m over 6 years in treatment I thought surely I would be undetectable by now but I was not really worried about it but now these crazy fluctuations I don’t know what to believe. My oncologist doesn’t really offer any input just a short “as long as your cbc is stable and you maintain mmr we don’t need to change anything”  

John, I share your frustration, but I'm afraid we both (and others) need to calm down. What you describe is what happens to me all the time now (in the past 4-5 years) at the same institution, which is famed.  Yes, they've tweaked things in their lab from time to time, and sometimes they even tell us mere mortals.  But, bottom line, there is so little difference between 0.08 and undetectable as to be scientifically designated "insignificant," and I have to school myself to let it go.  There is so much emphasis on TFR that our hearts get all fluttery at an undetectable, thinking maybe - maybe - we'll be one of the lucky elect.  Then, boom, back to what feels like a failure.  But it's not - it's just number trickery and we must resist getting sucked into the game.  The truth is still the same as when the drumbeat for TFR first began 10-15 years ago:  only about half of attempted TFR's are durable, and only about half of the CML world will even become eligible to try, so that in reality, only about 1/4 of CML patients will be able to stop treatment.  Could we please find a cure instead?