Having been there and done this, I wish there was something I could say that would ease your mind. I obviously know your fear. The only thing I can tell you is the mantra that all people faced with a serious issue are told. It's not something until they say it's something. Not knowing sucks but it is what it is. At least you have doctors that care and are on the ball.
Honestly, having had several major surgeries, you're so doped up that you don't really even care if it hurts and while there's discomfort, they keep you pretty comfortable.
It's hard enough to deal with not having anxiety but I can tell you, based on knowing some people with anxiety that have faced serious issues, your anxiety will take a back seat as you step up to the plate and deal with what you have to deal with and often, the reality of dealing with a real issue or threat is that anxiety lessens overall as your perspective changes.
Good luck and keep us in the loop.
Positive thoughts