The actual PSA number isn't as important as how much has it changed over time. It naturally increases with age. That is why for us old guys they suggest an annual PSA test. Mine was 1.0 +/- a point or two all my life until right after my 71st birthday when it went up to 5.4 in one year. So my primary care doctor said let's wait 30 days and test again. It came back as 4.8 so now off to the urologist for a biopsy. Yep, I had it, but only on one side and stage 1. Bone scan showed no spreading. 40 radiation treatments later my radiologist said to wait 3 months for another PSA and he would like to see a 50% drop in PSA, so he was looking for 2.5 or less. At the 3 month point Covid was just getting started so he waited another month for the test and it dropped to 0.84. He was excited and definitely I was too. Another 3 months went by and another text came back at 0.3.
They will never tell you that you are totally cured, but time will tell. All looks good so far. My next PSA is scheduled for May this year.