My heart goes out to you. Nothing as painful than seeing one’s child ill or suffering. You will have to put your trust in the medical care your daughter will receive and into your faith if you have that connection. I have stage 4 with bone metastasis in nearly every bone in my body. It hasn’t progressed since my diagnosis 2 1/2 years ago. I also have mets in the liver and they have ‘significantly reduced’ since being treated. All treatments are taxing and it is a new kind of living but your daughters stage 3 is not classified terminal as I understand. So it would be considered treatable instead. That’s us humans, not infallible. Our bodies go wrong sometimes but try to put your faith into all working out well for your daughter. Just concentrate one pointedly in believing that. Such a steady belief could be of great support to your daughter. She’ll see then that you are alright and she doesn’t have to worry about you. And you’ll help her believe that she will be fine