There have been advances in this particular cancer treatment which I did not have access to years ago. Radiation can and most likely will result problems for years if not forever. I understand your concern with reoccurrence however the option then for radiation would still be on the table. Our concern about the big "C" returning is forefront on most people's mind for years. It is only natural.
I recall at my five year mark the oncologist telling me that now my risk of return is that of the general population. To which I replied that it is now exactly where it was when I got cancer therefore I am not comforted by that statement. Now that I am older it is no longer a concern.
Have you been advised if you will have a followup medication?