DansBoobs gives good advice.
Ask your radiation oncologist to put numbers to the odds of the cancer coming back. For example, mine said that for me the odds of the cancer recurring with NO radiation were about 20%, but WITH radiation less than 5%. These are just my odds, yours may be different. So, for me, radiation it is -- a 15% drop is worth whatever the hassles are.
Also, ask if you can get a second opinion - everyone looks at the world through different eyes and it would help you a lot to talk to someone else and see what their take on things is.
As to clinical trials, make sure you understand exactly what you might be signing up for. These trials usual run with 2 different sets of treatment offered to patients. Ask exactly what the 2 treatments entail and what the possible outcomes of each are FOR YOUR SITUATION.
Good luck Mon and do update this blog so we know how you are getting on.
Knowledge is power and there will come a point when you know what it is that you want to do and, importantly, why.
Cheers, Esther