I think it's important for all of us to be familiar with tumor markers for what they can and cannot do for us. Here's a good reference piece to get started with. I was at my onc's yesterday and we had a good discussion, I ended up asking for a blood test which we'll use as a base (I've finished chemo and am two weeks out from my surgery)
I wanted to do the test now, before I started my radiation, mainly for my peace of mind that by focusing on my breasts we hadn't let the rest of me go unquestioned. Yes, if there is cancer elsewhere the chemo should have impacted it but that doesn't mean I don't want to rest on my chemo's laurels for even a second.
Here's the piece: