I am so very sorry about your baby's dx. Stage 4 is not hopeless but it is not not a good grade. I, personally, would not do chemo at this stage. You should let the vet give you all the details and then you can make your decision based on facts. If it were me I would give my baby pain drugs when the time came and let her live out her days as normal as possible. God bless you and your little one.
__________________  RIP my darling little Gina |