Hi Bogart and welcome!
I have to ask....why won't your Doc discuss thyroid with you? Maybe I'm missing something but the thyroid has nothing to do with prostate cancer 
The testosterone debate has been a long standing one in the medical arena so that one doesn't suprise me at all. On the other hand, Mayo of all places, should be more up to date. I say this of course, not knowing what all the considerations are either.
I am just curious as to why discussing thyroid, or potential thyroid issues would be of any harm???
Swim