Hello Thomas and welcome,
It is understandable that you feel the way you do... it is a common experience at diagnosis. However, given your test results it looks to me like you will be one of the majority good responders to TKI therapy. So you can be fairly certain, even at this early stage in your therapy, that you will live out your normal life span (whatever that may be) ... in other words you will live with CML rather than die from it.
I have included a pre-publication snapshot from our booklet about q RT-PCR in the hope that it might help answer some of you questions... it does underline what your doctor has already told you- i.e a poor sample. It also might be that q RT-PCR testing at diagnosis is not as accurate in assessing the disease level as cytogenetics. As your PH positive cells reduce (even if they cannot be detected under the microscope) to under 10% q RT-PCR testing will be very accurate and will take the place of cytogenetics etc.
I hope this adds to the reassurance that Richard has given you.
best wishes,
Sandy
See below for a brief explanation:
"In approximately 95% of cases, the Ph chromosome will be detected by routine cytogenetic analysis. However, in approximately half of the remaining 5% of cases, the Ph chromosome may not be visible, but the BCR-ABL1 fusion gene is identified by using molecular testing by PCR. For simplicity, any disease that contains the BCR-ABL1 fusion gene is referred to as Ph+ CML.
It has been shown that the BCR-ABL1 fusion gene is the single, definitive cause of Ph+ CML, and remains the key abnormality throughout the chronic phase (CP) of the disease.
Quantitative Reverse Transcriptase PCR (q RT-PCR)
A diagnosis, virtually every white cell in a blood or marrow sample tested will be leukaemic (Ph+) so the result should, in theory, be 100% Ph+. However, because there are higher levels of Ph+ cells present at diagnosis, the q RT-PCR test lacks accuracy at this stage. Thus results may vary between 50 and 100%.
A good diagnostic sample will contain equal amounts of transcripts of both a control gene and the abnormal gene (BCR-ABL1). The lowest acceptable level for a control gene in any one sample is 10,000 copies.
The result will show a relative proportion (expressed as a percentage) of how many leukaemic (BCR-ABL1 positive) cells are present over the total number of cells analysed in the blood sample.
Since the introduction of targeted therapy, it is agreed that at least in chronic phase CML, if an effective suppression of cells containing the BCR-ABL1 gene is reduced to the molecular level, the risk of disease progression is reduced significantly."
© CML Support Group 2014
