As Cheryl mentioned,
HPV-16 related HNC is usually in the oropharynx, like base of tongue, 90% of the time, as opposed to the oral tongue, which some say
HPV-16 may occurr there, but some say it could be misclassified as oral tongue, and be an extension of BOT cancer. Another is
HPV related cancer outside the oropharynx is found to respond differently. As far as RT after surgery, the ideal time is 4-6 weeks, but depends in healing.
Good luck.