@dbee
Quite a lot to decide. We have all been your dilema.

I am not sure where you information came from on radiation causing incontinence after a few years. That is not my expereince with information given to me by Mayo urologist, Mayo R/O, UFHPTI R/O. Of course can happen but not a forgone happening.

The radiation can for some cause problems on incontinence, drippling, more frequent urination, vilocity and on an on. Most of these reduce in being an issue over time. I for one had 30 rounds of proton radiation. I am at my 1.5 years since radiation stopped. I did not suffer from incontinence. I did for during treatments and for about a year after have increased urnination, increased urgency, drippling, etc. These slowly got better and better over time.

With all that it has to be your decision. If I could add to what you have posted would be to get a second opinion on your diagnosis and treatment options. That can help you decide. Just remember it is your body, your cancer, what quality of life you want, and your decision to make after seeing all side affects and outcomes of treatment options.
Good Luck!!