I am very sorry to hear you received this news. Having known people close to me that got cancer, I know what an impact the news can have. I stared in silence at my monitor for probably 5 minutes before typing this.
Whatever question pops into your mind between now and the oncologist visit, write it down and ask. Never be afraid to ask questions. Never hesitate to get a second opinion if you want to. Don't hesitate to go with your gut regarding your own treatment provided you run it by the doctors.
I wish I could take the pain and worry away from you, your family, your girlfriend, your friends - but I can't so all I can do is send my best wishes to all.