i was afraid of the same thing with my husband, i had heard from someone that the tumor would cut his airway off eventually, but in my husbands case, he had a muscle pulled up to cover the hole created by taking part of his jaw and cancer, so the last days of his life, he started having some spots on his neck and face and when i took him to dr, the doctor said that those spots were a type of skin cancer, that his immunities were gone and the cancer was taking over and that the tumor was growing out rather than inward like i feared because of the muscle that was pulled up to repair. He also had a lot of pain in his head that we were trying to get under control, they thought it was the trigemanal nerves causing the pain with my husband he just kind of quit using so much food in his tube and got restless, but he still was walking to the bathroom the day before he died. I noticed in the morning he hadn't moved much, but he seemed to be breathing better at first and then he fell into the rapid breathing and then just a couple shallow breaths and he was gone.He actually got clammy and had run a low grade temp that last day as well..he actually went pretty peacefully and had seemed to still know people just the day before. that was my experience.