Benfry
It's no longer true that you cannot have radiation a second time if there is a recurrence. I'm living proof of that. Plus I had the so called "maximum" the first time around of 72 GY.
The difference is now they have CyberKnife as a tool to use after standard IMRT.
If you're nervous, it's helpful to get an opinion from a CCC that is familar with the new developments in radiation. Unlike your father, I did not get clear margins with my surgery nor was my pathology report very good (perineural involvement)so the consensus was that if I did not get a second dose of radiation, the odds were that the tumor would come back a third time
Radiation is not easy but it's much better than a recurrence.
Charm