bad breath cancer

My dog had cancer tumors removed in his mouth and part of his tongue. Need help w / worse "sewer" breath.
It still have tumors that can not be removed, thus causing the smelly bacteria in your mouth and you can smell in the air. I spray deodorant on your dog skin – nothing works. Help!
you can get pills from a veterinarian of breath from the stomach not from the mouth the tablets to humans are called amplexus think so, but talk to your vet