My treatment also included radiation (with boost the last several treatments) on the lower half of my face and upper half of my neck, instead of IMRT. Best he could tell, the surgeon got all of the tumor and the one small area outside the tumor in the floor of mouth. Therefore, IMRT, as a targeted therapy, had nothing to target - like you describe of your mother's situation. Because I have never smoked, seldom drink alcohol and was HPV-, the team felt I needed aggressive treatment which the widespread radiation provided against a potentially and statistically aggressive cancer. It's a very personal decision - I chose to follow the team's advice and hit it with the big guns.

Also, regarding a gap in treatment - ask the radiologist to show you the bell curve for radiation effectiveness. It's a steady climb up to a certain point where it increases only minimally per additional treatment. My radiologist showed me this to reassure me it was okay when I had to miss 5 days (due to Thanksgiving closing the center and side affect making me sick). At the time of my gap in treatment, I had reached the point where I was past the steep climb and felt reassured it was okay to have the gap after seeing the bell curve.

Treatment is very tough as you are seeing, but there is healing aftewards. Everyone heals differently, but I would expect her to improve to a new normal following treatment.

Best wishes to your Mom as she continues her treatment.