Please dont make yourself nuts over this. I was faced with the same thing when I first got sick. I was told that I could go ahead and do the huge surgery and be very disfigured or try to cure it with chemo and radiation. Of course I chose the less invasive option and went thru chemo and rads. Unfortunately it came back and was successfully removed by a small surgery. Then it came back and the camcer was in my jawbone which was a stage IV. So I ended up doing a big surgery anyway.

Thinking back, I would have done the exact same thing. I had clear PET scans between each recurrence and felt great. You did what you thought was the best choice and unfortunately your dad has to go thru surgery anyway. That isnt something anyone could have predicted. Dont be so hard on yourself. I hope your father isnt second guessing himself either. Best of luck to your father with his recovery.