Hey Heather,
Just popped over here to take a peek and noticed your post. I had the same thing on my wrist and opted for the surgery. The surgeon and many other people told me I could have taken a book and smashed it down on the cyst to break it up. I know it sounds absurd, but the surgeon even told me this. Don't know if there's any truth to it though. If you look into it ask if they recommend going to PT or exercises afterward. My surgeon didn't and I don't have the full range of motion on that hand (doesn't like to bend up all the way). And I did lots of stretching as it was healing.

Best of luck with your decision - how did the half marathon go?