I've been on synthroid for 5 years, my thyroid issues predate my run in with cancer, and I've not experienced any negative side effects. My energy level is back, my memory is back and like everyone else I'm not cold anymore. I have a sister who has been on Synthroid nearly 40 years, she's not dealt with anything negative as a result either.

Cancer of Tongue, SCC early Stage 1, Dx 3/13/07, partial glossectomy 4/14/07 found no residual carcinoma and a granular cell tumor with pseudo epitheliomatous hyperplasia.