Welcome to Cancer Chat Evita although I'm sorry about your sister's diagnosis.

If you're able to get your sister's permission you will be able to speak to her medical team privately so have a chat and see if she is willing and if she is, you can then ask all the questions that are playing on your mind about her diagnosis, as well as the one you've mentioned above about her operation.

It sounds like you're doing a wonderful job of supporting your sister already, as I'm sure many of members will agree, but I'm going to include some information we have on our website for you to have a look at as well. 

Wishing your sister all the best with her operation when the time comes.

Kind regards, 

Steph, Cancer Chat Moderator