Friend with cancer - advice please

Hi everyone, 

I'm looking for some advice about my best friend who I live with and who has recently found out has cancer 

I think my best friend of over 10 years has cancer and she hasn't mentioned anything to me. We're both young (24yo) and spend most of our time together, she doesn't have a partner so we are each others main support and have been for a while. I found out from a few clues that I put together accidentally - I borrowed her laptop and saw pages open about cancer and bone pain etc, I also noticed she is reading a lot of books about dying and then found some pages she left around which she had written about cancer (she writes poetry and thoughts which included things around terminal cancer). 

She hasn't told me anything about the cancer but I know from the notes I found that she has known for some time, has told her boss and friends at work and that she has had surgery in the last year, I'm not sure when she found out but its possible she might not have told me as I have had some significant mental health problems over the last year but it hurts me so much that she might have been struggling with a diagnosis and hospital visits while I relied on her 

I completely want to respect her privacy and feel guilty for having seen some of the personal things she has written about this and I understand if she doesn't want to be treated differently and doesn't want every aspect of her life to be about the cancer but if there is more I can be doing I feel I need to know. If I have limited time left with her it would change my plans (going away for example) and a lot of things about our life. 

I don't know whether to bring it up with her or how, I don't know what's best for her or what I can do in the meantime to support her. At the moment I am trying to process my own feelings about it and find out more from websites like this so that I can focus on supporting her. I'd be really grateful for any advice from those who have cancer diagnoses or support those who do. 

thank you for your help and I hope you don't mind me using this forum for advice