I to was diagnosed with thyroid cancer and that was back in 1975. I had my thyroid removed, and 6 months later I was given radiation treatment, and then again 6 months after that. Since then I have had no trouble at all, as long as I take me medication everyday, and get my thyroid checked once a year to make sure the dose is correct. In all the years I've been taking synthroid I've only had my medication changed twice. By the way I was 19 when diagnosed,& 20 when I had the surgery.