In my own experience, as a 74-year-old, my first PSA reading of 10.9 and second a month later at 9.3 gave rise to a fast-track referral to the local hospital with a urology consultant (DRE showed no significant problems) who prescribed tamsulosin for two months. Then no real change in PSA so an MRI scan (Likert 3) followed by a biopsy with a diagnosis of Gleason 3+4 (later reduced to 3+3 after a second opinion which is another story). At the moment under AS. My last two PSA readings have been 12.93 (think I had an infection) and most recent was 9.9. Now, I know these levels look very high but my prostate is very large indeed at 94cm and several consultants I've spoken to haven't been too bothered about it. Of course, I do know I have Ca but my consultant says as long as the PSA remains around 11 there isn't a problem. PSA levels can be very relative and confusing.