I had proton therapy 5 years ago - at the time was 61yr, PSA 4.6, Gleason 6, T2 and I had just finished rehab for a slight heart attack that required a stent placement. My 5 yr PSA is 0.17 and I have not had any side effects. The treatment is completely noninvasive. Unlike photon radiation which goes clear thru the body, proton can be stopped at the tumor so very minimal damage would be done to any surrounding organs or tissue. It takes about 1/2 hour out of your day and then the rest of the time is yours for any activity you wish.
The previous post mentioned the fact that it took 9 weeks out of your life. Here's my thinking on that. Any intervention you choose will have a substantial impact on your quality of life so you had better be ready to accept the side effects and if I have to give up 9 weeks to have a great quality of life, I consider this a good return.
Please go to protonbob.com - at this site you can read over 100 testimonials, there are phone numbers you can use to call men who have gone thru the procedure and you can get much more info on proton.
One last thing - I have never seen a hospital like Loma Linda - it's doctors and support staff are wonderful and the prostate cancer support network is superb. This is a very serious issue, but we felt like we were on vacation while there.
Hope this helps and good luck with whatever modality you choose.