The throat cancer life expectancy really depends on the stage it's at when you find it. There's stage I, which is a pretty small tumor, less than 1 inch across, that's just in one place. I found on the NIH site that 90% of people at this stage can be cured!
It goes up to stage IV, where the tumor is bigger and has also spread to other places. Info on throat cancer life expectancy for stage IV is kind of hard to find, but the best source I found said about 30% of patients at that stage live for five or more years.