Hi I Had Thyroid Cancer 12 Years Ago Resulting In

Hi I had thyroid cancer 12 years ago resulting in half of my thyroid was taken out. I have never had medicines for my thyroid just bloodwork and ultrasounds. My labs come back In normal range. But looking at bloodwork for the past 2 years my levels went from 1.92 uIU/ml down to 1.27 uIU/ml. Should I have a concern