Some people (clinicians and non-clinicians) have that mentality for various reasons: Take it all and no one will ever know if that was "overkill" (pardon the phrase). A clinician certainly wouldn't want you to be disappointed and have to go through this again. But if you only had a tumor in your right lung, would you want both lungs removed? Also, 6 years ago, I asked a LOT of Q. I was told that radioactive iodine is no longer the typical treatment. It was MANY years ago (decades?), but it wasn't 6 years ago. Again, these were my experiences. No matter where one goes for healthcare, a second opinion about the treatment plan could be helpful. And you have the right to say no to a total thyroidectomy. This position is called conservative treatment, do only what's necessary. If things change on the other half of my T, then I'd have that removed. It's a common surgery, very close to the surface of the skin.