Oh my dear I'm so sorry! and I'm sorry it took me so long to respond, I got food poisoning from a greasy spoon diner - yuck!
Okay. Until they actually do a biopsy, they cannot know what kind of tissue it is. They can see that it's abnormal tissue, but can't know whcih kind of abnormal tissue. See the difference?
Because of HMOs and needing to keep the cost of things down, and since the gland is sooo tiny, rather than doing the usual steps that doctors do for cancer, they just take out all the bad tissue straight away. Now they should NOT do a total removal of the thyroid, that would be stupid! So definitely get a second opinion or different doctor if that is indeed what he said. I doubt it tho since he mentinoed the radioactive iodine.
Iodine is always taken up by the thyroid. So when you take radioactive iodine, the radiation goes to the thyroid to kill cancer cells and unfortunately healthy thyroid cells too.
Thyroid issues tend to run in families, and they happen in areas where there is a lot of toxicity, such as places that have toxic waste dump sites nearby and use well water. Even places we tend to think of as clean, like Oregan and Washington, have super-high rates of thyroid disease because of ground water pollution etc.
Here's a link that will give you a good overview on the situation.