There is always hope. My brother survived leukemia with a bone marrow transplant about 35 years now. My mother survived both pancreatic cancer (very low survival rate) and breast cancer. She finally passed away but not due to either of those diseases. Keep the faith, your wife and family will be in my prayers.
Very sorry for your loss. I had two Labs, Max & Casey. They were great hunters and great companions. I miss them a lot but especially when Fall comes. Hunting will never be the same without them. Take comfort from your great memories.