Well @Artferret, my oncologist confirmed that my thumb pain was almost certainly from Letrozole. Considering that I am also battling bone density issues, and the thumb is preventing me from doing my weightlifting at full strength, her decision was to give me one month’s holiday from everything before changing back to Tamoxifen.
Everyone is different but considering my particular situation, she feels this is the best thing to do. I made it through 3 years and 3 months on Letrozole. My first 2 years on Tamoxifen were relatively side effect free, so I am hopeful that it will be ok second time around too. She said we will see how I go but is hopeful I can get a few more years on Tamoxifen. She would like me to stay on anti-hormone therapy for a while yet. Our original plan was 10 years. That is 4 years and 9 months to go!
Will be interesting to see how long it takes for the thumb to get better.