Hello grace2024 and welcome to the forum, i too have prostate cancer and the only time i know of when you get  a number like that is with a PSA score, PSA means Prostate Specific Antigen which is a protein in your blood made by the prostate, it is normal and harmless, normally even for someone your friends age it should be well under 10, only rising if the prostate is damaged or infected as with cancer. As you say he has had prostate cancer for four years and no treatment his original diagnosis could have caught the cancer early enough to be put on active surveillance, which just means regular tests to monitor his condition, Grace a PSA score of 37 does not mean the cancer has spread, i know people who had a PSA of over a thousand with no spread. I am surprised he has not started treatment though, maybe there are other health issues as well as dementia they have to consider. I know having dementia will make some treatments difficult at best and others can effect the memory, I don't even know if your friend could manage a scan or biopsy to identify what stage the cancer is at and how benign or aggressive it is, as a Gleason score would show how aggressive the cancer is and a scan would show any spread. Grace ask the doctor about a biopsy and a scan and what treatment he may be put on, please take car, Eddie