Hello, a year and a half after being diagnosed, my figure at 12 months 0.1 at 15 months 0.009 and now at 18 months 0.01 all this with 400 mg of imatinib and being 23 yo, I know it's not alarming but I can't finish understand what this increase may be due to, taking a relatively short time of treatment with imatinib, he also told me that it was at the limit of complete response, when I had understood that this limit was 0.1, any idea? Has anyone experienced something similar with imatinib? Is this situation normal?
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increment, imatinib, 18 months ¿
It may look like an uptick but the difference in the two is very insignificant at .001. That is essentially no difference and you are maintaining a good MMR. Congrats.
Two important parameters that describe the quality of quantitative data are accuracy and precision.
Accuracy is the degree that measurements equal the actual or true quantity in the theoretical absence of variability. An accuracy error is a consistent shift in the results away from the true quantity.
Precision is the random variation of repeated measurements.
The precision of PCR testing can have a variance range of 20 - 80% or close to one log and depends strongly on routine calibration of the equipment. The difference between your 0.009 measurement and recent 0.01 is within the precision of the test and represents "noise" variation. You have had 'no change' in six months in any meaningful sense. And ...
The accuracy of the PCR test decreases significantly below 0.1% result. Any value below 0.01 is not very accurate and often indistinguishable with non-detection. This is why research facilities often do not report PCR values at the third decimal place (X.XX(X) <-----). You are at that threshold which is a very good place.
PCR testing is a "canary" in the mine shaft early warning device and in that regard is very useful. It lets a patient know whether there is a trend (up or down) which may need attention long before disease takes root or celebration where whiskey and wine are in order.
An important fact based on years of CML research is that cytogenetic remission as determined by FISH (= zero) (PCR < ~1.0%) is the standard for 95% progression free survival. Patients whose PCR tests measure below 1.0% have beaten CML. You are two logs below that level. There are no CML cells to be seen. They are too few in number to show up. I hope this puts things in perspective.