@watsohj
A lot of possibilities while you monitor your PSA that have come about in the last eight years. These newer non invasive tests include ExoDx urine test, and PSE blood tests. These are used to help in determination of going forward with a biopsy in light of the MRI showing nothing. In your case without any targeted lesion to sample would be a full on grid. I don’t know if part of your PSA test is the free PSA percentage. It would be helpful to add some of your original diagnostic’s from eight years ago, like your MRI and biopsy results. FT is known to just kick the can down the road. You are still at a good age if something is brewing to have many options. I would continue to clearly monitor. What does your Doctor say?

@watsohj
You should be having a PSMA PET scan. The MRI may not find anything, but somethings creating that PSA.

Frequently the MRI does not show cancer, which is very aggressive inside the prostate. The only way to find it is to do a biopsy that covers a lot of the area left of the prostate, Or do a prostatectomy. I wouldn’t do anything until the PET scan is done.

Hopefully you’re not in Canada and can get this done since your PSA is so high. It is guaranteed to find whatever’s causing this problem..

It is possible that during focal therapy they only removed a small portion of your prostate. In that case rising to 4.2 may be just normal for your age. I’d want the pet scan though to prove it is normal.