I finally got my endocrinologist on the phone to discuss the results. I have little to report. He says either the "wait & see" course or the "surgery & treatment" course are reasonable, but recommends we "wait & see." It makes sense, but it isn't very satisfying. There are a lot of things we just don't know.
He thinks because my thyroglobulin levels have been slightly elevated but stable that cancer has been present for awhile but not growing (or growing very slowly). Or it could be new growth, if minimal. We don't know.
Because nothing appeared on the last radioactive iodine scan, there isn't a very reliable way to detect the extent of any spread (if any). Maybe it is in that one place; maybe more. We don't know.
We could do surgery to remove what we can find and follow up with a radioactive iodine treatment. Surgery (especially on the site of a previous procedure) has inherent risks. Will it minimize any chance of further recurrence or growth? We don't know.
So we don't really know how much cancer is present, how long it has been present, how fast it is growing, how likely it is to continue to grow or spread nor whether surgery & further treatment would provide any benefit at all. So we do surgery anyway, and take the risks now. Or we wait & see.