How do I know if my dog is nearing the end of their life due to cancer?

It's tough to say, and it's a very personal decision every owner has to make. My advice is when your dog is having more bad days than good days or when your dog stops doing the behaviors that make them happy. That's often their interaction with their owners or their pack members. It may be that it's getting time, at that point, that the dog doesn't feel very well and may be getting close, but that is a decision typically that's between you, your family members, and your veterinary team. We have that discussion to see when everybody thinks it's time.