I wouldn't know half as much as I know about childhood cancer and childhood cancer research if she hadn't shared her story about her son Ronan," Swift told the crowd. "The thing about childhood cancer is that it's really, really hard to talk about. And it's really not something that you bring up...but the fact that she brought it up, she had this blog called Rockstar Ronan and I would read it every night. And in it was this account of what it was like to watch cancer take over my life.