Hi, JoyDiane, welcome to the site! I am roughly your age and my tumor was roughly the size of yours...your question of radiation vs surgery is the one that almost all of us here struggled to answer for weeks, months, even longer for some. Someone will be along with great answers about exact facts and figures for you, I'm sure. It is such a personal decision and one that, unfortunately, only you can make. Sounds like you are on the right track to make a well-informed decision...one that is NOT easy to make. But, we'll help in any way we can (sorry I can't be of more help w/ #'s for you). I chose surgery over radiation for various reasons, but both approaches have risks and issues...surgery, obviously has the potential of some pretty serious issues, as Syl points out.
Have you contacted the ANA office yet? They can send you a wealth of information that can be very helpful to you in your research. You can request info from this website or you can contact them by phone at 770-205-8211. There are very nice and would be glad to hear from you.
Best of luck to you,
Cindy