If by the final stage of throat cancer you mean the most advanced stage, that’s called stage IV. That’s when the primary tumor has grown quite large, like more than 2 inches across, and has spread into other parts of the head, neck or lymph nodes, or even around the body.
Treatment can include some combination of surgery, radiation and chemotherapy. However, sometimes in the final stage of throat cancer it’s too advanced to be cured, so then treatment focuses on alleviating symptoms and making life as comfortable as possible.
I feel for you, I have not had any form of cancer but have lost family members due to it, I admire your strength by getting through it.