The usual first line of treatment for a recurrence is surgery whether in the oral tongue or oropharynx. Reirridation can be done or Chemoradiation, which is being done more often now, after resection, mainly talking about oropharynx, which is my type, has better outcome than surgery alone, and depends on a number of factors including the location, amount of prior radiation, total Gy, toxicity level to vital structures, the RO's experience, etc., even age and time between prior radiation.

Good luck with your scan.