Gino,
I also felt devastated when I felt I had recovered reasonable well from surgery, had what seemed to be a fairly clear pathology report, and then heard from my tumor board that they thought I needed to go ahead with radiation. After lots of questioning, I decided they had evidently thought it through and had valid reasons for their concern (I was 39 at the time and the cancer appeared to have some aggressive traits). Radiation was tough to endure, as you will read over and over on this site, but thankfully I've managed to go almost 17 years since then with no recurrence. I didn't have the benefit of some of the more recent radiation techniques, but my quality of life is still great, and I have no regrets about having had an aggressive treatment approach.
If you go ahead with radiation, you'll find plenty of support and advice here to help you get through it.
Cathy