Old Cajun, get a second opinion. There are bad Vets and there are great Vets. I never settle for just one diagnosis. When it comes to my Animal, I get another Vet to look and see what going on.
A Vet I took my Cat to, told me my animal had an incurable disease and had to be put down. I put my animal back in the carrier and took him to another Vet. The new guy found three bad teeth and he removed them. My Cat is just fine now and doing great. Always get a second opinion when it comes to putting the animal down.
Seek the -A- Vets. Not the -D- Vets. Your Dog is worth a second look. Find a Cancer specialist.