Hi, I had a total thyroidectomy in 2012, with RAI and this past April had 40 lymph nodes removed, 7 of which were positive for papillary cancer recurrence. I just had my follow-up bloodwork and am on 125 Synthroid 8x/week. My Tg was 6.3, down from 23.7 and my TSH is 0.77. I was told that the Tg is still high, since it should be 0 and this means there still could be residual tumors although invisible on US. Why do I need to have lower than normal thyroid levels to suppress the tumor growth?
Hello, TG or thyreoglubuline is a glycoprotein, so a protein, produced in your thyroid gland. So when your thyroid gland is completely removed (total thyroidectomy) or destroyed by radioactive sodium, the TG level should in theory be zero as there is no thyroid tissue level left. In cases of some thyroid cancer like papillary cancer the TG level is a parameter to follow up the disease. So if the TG level is increasing, that might be a sign that the cancer has come back. So after removing the lymph nodes it's a good sign that the level of TG is going down, but I agree that the level is still too high. So it's not a question of suppressing, it's rather a question of follow up of your cancer. The difficult part is when levels are still high and there's nothing to see on the ultrasound, where are there still cancer cells? So a Ct scan of the neck and chest might give information as well as a nuclear scan. Hope this answered your question