I am very sorry to read about your wifes situation, I really like how you've managed to be creative in your craft.Though I cannot give you a certain answer for your problem, I felt that giving you some support would be good, I recommend alot of research on this subject. When I read this I did some research on my own, and it turns out, there are alot of Wiccans who have been able to use magick to cure and help cure their cancer.
I found this page that seems rather reliable if you may, though I don't very much trust the internet.Might I recommend looking online to see if you find any cancer pagan support groups?
I think that might give you a hint for where to start, remember that you shouldn't just relay on magick, medicine is the evolution of the craft in a popular term, so trust your doctor too. Many blessings and good luck.
I am sorry if this information wasn't of any use to you.