Welcome, so sorry you have to be here.

Being a smoker is most likely what caused this cancer if it is HPV- and unfortunately as others have said, it is harder to treat and has a high recurrence rate. It also is very aggressive. It is great news that your surgeons were able to remove all of the tumor as well as get clear margins. You are definitely on the right track. That being said, my advice, for sure get another opinion so you are aware of all the options available to you, but also I would not hesitate whatsoever on treatment. You just don't want to waste any time or make any sort of compromises with your health. If you decided against treatment, and if it came back, you wouldn't want to be left with any regrets about not doing everything you could for the best possible outcome. Everyone here has either been through it personally or has cared for someone who has, and we can all help you get through it.

Best of luck and please keep us posted.