I have just finished a 5 session proton treatment for my prostate cancer at Mayo Phoenix and I did not take the Lupron shot that the radiation oncologist wanted to jab me with. I had a PSA of 2.9. I had 5 positive cores out of 30 and the 5 were all from the area on the MRI that showed the lesion. I had 3 cores that were 3-4 and two that were 4-3 that put me in the unfavorable intermediate risk category. I was also a T1c which means that it could not be felt by a DRE only on the MRI. I had only one unfavorable item and that was my 4-3 Gleason score. My PSA was less than 10 and my % of positive cores was way less than 50%. Then there is my age which is 73 and like your grandfather I am fit and active. The article in Radiation Oncology called Radiotherapy with or without androgen deprivation therapy in intermediate risk prostate cancer shows that in men over 70 there was no difference between RT alone and RT+ADT Another article to Google is "The role of proton beam therapy for patients with intermediate and high risk prostate cancer. Age seems to be a factor in the studies I have researched, and I am glad I am over 70. I also had a PSMA Pet scan that showed my cancer was confined to only the prostate. At our age if your grandfather and I get 15 years we are in our 90's. All I know is the side effects for someone of our age is not good and he might not be as active as he is now. It also effects the brain. Read the side effects that the drug causes online. Good luck to you and your grandfather.