And now for something different:
I have been off Sprycel for nine months testing whether I can stay off Sprycel and maintain remission. I was mostly successful, but did notice a slow rise from PCRU into MMR. I was still safe to stay off Sprycel (20mg), but decided last month to test if resuming Sprycel would drop me back down into PCRU. Although I didn't have to - I was curious - so I restarted.
Within days, my thyroid became incredibly painful and my temperature elevated. Heart beat went up to the mid-80's resting. And my TSH plummeted. Strange, my thyroid hormone level remained normal, but apparently did not need any stimulating hormone to keep it there. I do expect that my hyperthyroid will shift into a hypothyroid down the road. I'll just have to monitor.
It seems that TKI's (second generation in particular) can cause thyroid dysfunction. After being off Sprycel for so long with apparent immune system success attacking CML - an auto-immune response was set up against my thyroid. This is conjecture on my part. I do suspect I am having an auto-immune attack on my thyroid (thyroiditis). I have an appointment with an endocrinologist to confirm. The inflammation is not constant - comes and goes, but has been every day since re-starting Sprycel. Taking an ibuprofen (first time in years) alleviates the discomfort.
Reading up on this (see link above) - it does seem that there is a correlation between thyroid dysfunction and TKI's.
My recommendation to patients is to have their Thyroid function tested as part of their PCR testing schedule.
p.s. if my PCR drops back one log (essentially to PCRU) - I'm resuming my cessation. Thyroid and TKI's don't go well together.