We took our lovely collie cross to the vet a few weeks ago thinking he was constipated. Unfortunately we were told yesterday that it was prostate cancer and it is just a matter of keeping him comfortable until we put him to sleep when he is suffering. The tumour is pressing on his rectum so it is hard for him to poop. He seems okay in himself but has now taken a downturn and is peeing blood and his tail has dropped. We were supposed to go for a scan for confirmation on Tuesday but my dh thinks it is kinder just to get it done before he starts to really suffer. I am devastated for my poor little dog but I don't want him to be in pain. How do we know when is the right time?